diff options
Diffstat (limited to 'deps/npm/node_modules/mississippi/node_modules/through2/node_modules/readable-stream/doc/stream.markdown')
| -rw-r--r-- | deps/npm/node_modules/mississippi/node_modules/through2/node_modules/readable-stream/doc/stream.markdown | 1760 |
1 files changed, 0 insertions, 1760 deletions
diff --git a/deps/npm/node_modules/mississippi/node_modules/through2/node_modules/readable-stream/doc/stream.markdown b/deps/npm/node_modules/mississippi/node_modules/through2/node_modules/readable-stream/doc/stream.markdown deleted file mode 100644 index 0bc3819e63..0000000000 --- a/deps/npm/node_modules/mississippi/node_modules/through2/node_modules/readable-stream/doc/stream.markdown +++ /dev/null @@ -1,1760 +0,0 @@ -# Stream - - Stability: 2 - Stable - -A stream is an abstract interface implemented by various objects in -Node.js. For example a [request to an HTTP server][http-incoming-message] is a -stream, as is [`process.stdout`][]. Streams are readable, writable, or both. All -streams are instances of [`EventEmitter`][]. - -You can load the Stream base classes by doing `require('stream')`. -There are base classes provided for [Readable][] streams, [Writable][] -streams, [Duplex][] streams, and [Transform][] streams. - -This document is split up into 3 sections: - -1. The first section explains the parts of the API that you need to be - aware of to use streams in your programs. -2. The second section explains the parts of the API that you need to - use if you implement your own custom streams yourself. The API is designed to - make this easy for you to do. -3. The third section goes into more depth about how streams work, - including some of the internal mechanisms and functions that you - should probably not modify unless you definitely know what you are - doing. - - -## API for Stream Consumers - -<!--type=misc--> - -Streams can be either [Readable][], [Writable][], or both ([Duplex][]). - -All streams are EventEmitters, but they also have other custom methods -and properties depending on whether they are Readable, Writable, or -Duplex. - -If a stream is both Readable and Writable, then it implements all of -the methods and events. So, a [Duplex][] or [Transform][] stream is -fully described by this API, though their implementation may be -somewhat different. - -It is not necessary to implement Stream interfaces in order to consume -streams in your programs. If you **are** implementing streaming -interfaces in your own program, please also refer to -[API for Stream Implementors][]. - -Almost all Node.js programs, no matter how simple, use Streams in some -way. Here is an example of using Streams in an Node.js program: - -```js -const http = require('http'); - -var server = http.createServer( (req, res) => { - // req is an http.IncomingMessage, which is a Readable Stream - // res is an http.ServerResponse, which is a Writable Stream - - var body = ''; - // we want to get the data as utf8 strings - // If you don't set an encoding, then you'll get Buffer objects - req.setEncoding('utf8'); - - // Readable streams emit 'data' events once a listener is added - req.on('data', (chunk) => { - body += chunk; - }); - - // the end event tells you that you have entire body - req.on('end', () => { - try { - var data = JSON.parse(body); - } catch (er) { - // uh oh! bad json! - res.statusCode = 400; - return res.end(`error: ${er.message}`); - } - - // write back something interesting to the user: - res.write(typeof data); - res.end(); - }); -}); - -server.listen(1337); - -// $ curl localhost:1337 -d '{}' -// object -// $ curl localhost:1337 -d '"foo"' -// string -// $ curl localhost:1337 -d 'not json' -// error: Unexpected token o -``` - -### Class: stream.Duplex - -Duplex streams are streams that implement both the [Readable][] and -[Writable][] interfaces. - -Examples of Duplex streams include: - -* [TCP sockets][] -* [zlib streams][zlib] -* [crypto streams][crypto] - -### Class: stream.Readable - -<!--type=class--> - -The Readable stream interface is the abstraction for a *source* of -data that you are reading from. In other words, data comes *out* of a -Readable stream. - -A Readable stream will not start emitting data until you indicate that -you are ready to receive it. - -Readable streams have two "modes": a **flowing mode** and a **paused -mode**. When in flowing mode, data is read from the underlying system -and provided to your program as fast as possible. In paused mode, you -must explicitly call [`stream.read()`][stream-read] to get chunks of data out. -Streams start out in paused mode. - -**Note**: If no data event handlers are attached, and there are no -[`stream.pipe()`][] destinations, and the stream is switched into flowing -mode, then data will be lost. - -You can switch to flowing mode by doing any of the following: - -* Adding a [`'data'`][] event handler to listen for data. -* Calling the [`stream.resume()`][stream-resume] method to explicitly open the - flow. -* Calling the [`stream.pipe()`][] method to send the data to a [Writable][]. - -You can switch back to paused mode by doing either of the following: - -* If there are no pipe destinations, by calling the - [`stream.pause()`][stream-pause] method. -* If there are pipe destinations, by removing any [`'data'`][] event - handlers, and removing all pipe destinations by calling the - [`stream.unpipe()`][] method. - -Note that, for backwards compatibility reasons, removing [`'data'`][] -event handlers will **not** automatically pause the stream. Also, if -there are piped destinations, then calling [`stream.pause()`][stream-pause] will -not guarantee that the stream will *remain* paused once those -destinations drain and ask for more data. - -Examples of readable streams include: - -* [HTTP responses, on the client][http-incoming-message] -* [HTTP requests, on the server][http-incoming-message] -* [fs read streams][] -* [zlib streams][zlib] -* [crypto streams][crypto] -* [TCP sockets][] -* [child process stdout and stderr][] -* [`process.stdin`][] - -#### Event: 'close' - -Emitted when the stream and any of its underlying resources (a file -descriptor, for example) have been closed. The event indicates that -no more events will be emitted, and no further computation will occur. - -Not all streams will emit the `'close'` event. - -#### Event: 'data' - -* `chunk` {Buffer|String} The chunk of data. - -Attaching a `'data'` event listener to a stream that has not been -explicitly paused will switch the stream into flowing mode. Data will -then be passed as soon as it is available. - -If you just want to get all the data out of the stream as fast as -possible, this is the best way to do so. - -```js -var readable = getReadableStreamSomehow(); -readable.on('data', (chunk) => { - console.log('got %d bytes of data', chunk.length); -}); -``` - -#### Event: 'end' - -This event fires when there will be no more data to read. - -Note that the `'end'` event **will not fire** unless the data is -completely consumed. This can be done by switching into flowing mode, -or by calling [`stream.read()`][stream-read] repeatedly until you get to the -end. - -```js -var readable = getReadableStreamSomehow(); -readable.on('data', (chunk) => { - console.log('got %d bytes of data', chunk.length); -}); -readable.on('end', () => { - console.log('there will be no more data.'); -}); -``` - -#### Event: 'error' - -* {Error Object} - -Emitted if there was an error receiving data. - -#### Event: 'readable' - -When a chunk of data can be read from the stream, it will emit a -`'readable'` event. - -In some cases, listening for a `'readable'` event will cause some data -to be read into the internal buffer from the underlying system, if it -hadn't already. - -```javascript -var readable = getReadableStreamSomehow(); -readable.on('readable', () => { - // there is some data to read now -}); -``` - -Once the internal buffer is drained, a `'readable'` event will fire -again when more data is available. - -The `'readable'` event is not emitted in the "flowing" mode with the -sole exception of the last one, on end-of-stream. - -The `'readable'` event indicates that the stream has new information: -either new data is available or the end of the stream has been reached. -In the former case, [`stream.read()`][stream-read] will return that data. In the -latter case, [`stream.read()`][stream-read] will return null. For instance, in -the following example, `foo.txt` is an empty file: - -```js -const fs = require('fs'); -var rr = fs.createReadStream('foo.txt'); -rr.on('readable', () => { - console.log('readable:', rr.read()); -}); -rr.on('end', () => { - console.log('end'); -}); -``` - -The output of running this script is: - -``` -$ node test.js -readable: null -end -``` - -#### readable.isPaused() - -* Return: {Boolean} - -This method returns whether or not the `readable` has been **explicitly** -paused by client code (using [`stream.pause()`][stream-pause] without a -corresponding [`stream.resume()`][stream-resume]). - -```js -var readable = new stream.Readable - -readable.isPaused() // === false -readable.pause() -readable.isPaused() // === true -readable.resume() -readable.isPaused() // === false -``` - -#### readable.pause() - -* Return: `this` - -This method will cause a stream in flowing mode to stop emitting -[`'data'`][] events, switching out of flowing mode. Any data that becomes -available will remain in the internal buffer. - -```js -var readable = getReadableStreamSomehow(); -readable.on('data', (chunk) => { - console.log('got %d bytes of data', chunk.length); - readable.pause(); - console.log('there will be no more data for 1 second'); - setTimeout(() => { - console.log('now data will start flowing again'); - readable.resume(); - }, 1000); -}); -``` - -#### readable.pipe(destination[, options]) - -* `destination` {stream.Writable} The destination for writing data -* `options` {Object} Pipe options - * `end` {Boolean} End the writer when the reader ends. Default = `true` - -This method pulls all the data out of a readable stream, and writes it -to the supplied destination, automatically managing the flow so that -the destination is not overwhelmed by a fast readable stream. - -Multiple destinations can be piped to safely. - -```js -var readable = getReadableStreamSomehow(); -var writable = fs.createWriteStream('file.txt'); -// All the data from readable goes into 'file.txt' -readable.pipe(writable); -``` - -This function returns the destination stream, so you can set up pipe -chains like so: - -```js -var r = fs.createReadStream('file.txt'); -var z = zlib.createGzip(); -var w = fs.createWriteStream('file.txt.gz'); -r.pipe(z).pipe(w); -``` - -For example, emulating the Unix `cat` command: - -```js -process.stdin.pipe(process.stdout); -``` - -By default [`stream.end()`][stream-end] is called on the destination when the -source stream emits [`'end'`][], so that `destination` is no longer writable. -Pass `{ end: false }` as `options` to keep the destination stream open. - -This keeps `writer` open so that "Goodbye" can be written at the -end. - -```js -reader.pipe(writer, { end: false }); -reader.on('end', () => { - writer.end('Goodbye\n'); -}); -``` - -Note that [`process.stderr`][] and [`process.stdout`][] are never closed until -the process exits, regardless of the specified options. - -#### readable.read([size]) - -* `size` {Number} Optional argument to specify how much data to read. -* Return {String|Buffer|Null} - -The `read()` method pulls some data out of the internal buffer and -returns it. If there is no data available, then it will return -`null`. - -If you pass in a `size` argument, then it will return that many -bytes. If `size` bytes are not available, then it will return `null`, -unless we've ended, in which case it will return the data remaining -in the buffer. - -If you do not specify a `size` argument, then it will return all the -data in the internal buffer. - -This method should only be called in paused mode. In flowing mode, -this method is called automatically until the internal buffer is -drained. - -```js -var readable = getReadableStreamSomehow(); -readable.on('readable', () => { - var chunk; - while (null !== (chunk = readable.read())) { - console.log('got %d bytes of data', chunk.length); - } -}); -``` - -If this method returns a data chunk, then it will also trigger the -emission of a [`'data'`][] event. - -Note that calling [`stream.read([size])`][stream-read] after the [`'end'`][] -event has been triggered will return `null`. No runtime error will be raised. - -#### readable.resume() - -* Return: `this` - -This method will cause the readable stream to resume emitting [`'data'`][] -events. - -This method will switch the stream into flowing mode. If you do *not* -want to consume the data from a stream, but you *do* want to get to -its [`'end'`][] event, you can call [`stream.resume()`][stream-resume] to open -the flow of data. - -```js -var readable = getReadableStreamSomehow(); -readable.resume(); -readable.on('end', () => { - console.log('got to the end, but did not read anything'); -}); -``` - -#### readable.setEncoding(encoding) - -* `encoding` {String} The encoding to use. -* Return: `this` - -Call this function to cause the stream to return strings of the specified -encoding instead of Buffer objects. For example, if you do -`readable.setEncoding('utf8')`, then the output data will be interpreted as -UTF-8 data, and returned as strings. If you do `readable.setEncoding('hex')`, -then the data will be encoded in hexadecimal string format. - -This properly handles multi-byte characters that would otherwise be -potentially mangled if you simply pulled the Buffers directly and -called [`buf.toString(encoding)`][] on them. If you want to read the data -as strings, always use this method. - -Also you can disable any encoding at all with `readable.setEncoding(null)`. -This approach is very useful if you deal with binary data or with large -multi-byte strings spread out over multiple chunks. - -```js -var readable = getReadableStreamSomehow(); -readable.setEncoding('utf8'); -readable.on('data', (chunk) => { - assert.equal(typeof chunk, 'string'); - console.log('got %d characters of string data', chunk.length); -}); -``` - -#### readable.unpipe([destination]) - -* `destination` {stream.Writable} Optional specific stream to unpipe - -This method will remove the hooks set up for a previous [`stream.pipe()`][] -call. - -If the destination is not specified, then all pipes are removed. - -If the destination is specified, but no pipe is set up for it, then -this is a no-op. - -```js -var readable = getReadableStreamSomehow(); -var writable = fs.createWriteStream('file.txt'); -// All the data from readable goes into 'file.txt', -// but only for the first second -readable.pipe(writable); -setTimeout(() => { - console.log('stop writing to file.txt'); - readable.unpipe(writable); - console.log('manually close the file stream'); - writable.end(); -}, 1000); -``` - -#### readable.unshift(chunk) - -* `chunk` {Buffer|String} Chunk of data to unshift onto the read queue - -This is useful in certain cases where a stream is being consumed by a -parser, which needs to "un-consume" some data that it has -optimistically pulled out of the source, so that the stream can be -passed on to some other party. - -Note that `stream.unshift(chunk)` cannot be called after the [`'end'`][] event -has been triggered; a runtime error will be raised. - -If you find that you must often call `stream.unshift(chunk)` in your -programs, consider implementing a [Transform][] stream instead. (See [API -for Stream Implementors][].) - -```js -// Pull off a header delimited by \n\n -// use unshift() if we get too much -// Call the callback with (error, header, stream) -const StringDecoder = require('string_decoder').StringDecoder; -function parseHeader(stream, callback) { - stream.on('error', callback); - stream.on('readable', onReadable); - var decoder = new StringDecoder('utf8'); - var header = ''; - function onReadable() { - var chunk; - while (null !== (chunk = stream.read())) { - var str = decoder.write(chunk); - if (str.match(/\n\n/)) { - // found the header boundary - var split = str.split(/\n\n/); - header += split.shift(); - var remaining = split.join('\n\n'); - var buf = new Buffer(remaining, 'utf8'); - if (buf.length) - stream.unshift(buf); - stream.removeListener('error', callback); - stream.removeListener('readable', onReadable); - // now the body of the message can be read from the stream. - callback(null, header, stream); - } else { - // still reading the header. - header += str; - } - } - } -} -``` - -Note that, unlike [`stream.push(chunk)`][stream-push], `stream.unshift(chunk)` -will not end the reading process by resetting the internal reading state of the -stream. This can cause unexpected results if `unshift()` is called during a -read (i.e. from within a [`stream._read()`][stream-_read] implementation on a -custom stream). Following the call to `unshift()` with an immediate -[`stream.push('')`][stream-push] will reset the reading state appropriately, -however it is best to simply avoid calling `unshift()` while in the process of -performing a read. - -#### readable.wrap(stream) - -* `stream` {Stream} An "old style" readable stream - -Versions of Node.js prior to v0.10 had streams that did not implement the -entire Streams API as it is today. (See [Compatibility][] for -more information.) - -If you are using an older Node.js library that emits [`'data'`][] events and -has a [`stream.pause()`][stream-pause] method that is advisory only, then you -can use the `wrap()` method to create a [Readable][] stream that uses the old -stream as its data source. - -You will very rarely ever need to call this function, but it exists -as a convenience for interacting with old Node.js programs and libraries. - -For example: - -```js -const OldReader = require('./old-api-module.js').OldReader; -const Readable = require('stream').Readable; -const oreader = new OldReader; -const myReader = new Readable().wrap(oreader); - -myReader.on('readable', () => { - myReader.read(); // etc. -}); -``` - -### Class: stream.Transform - -Transform streams are [Duplex][] streams where the output is in some way -computed from the input. They implement both the [Readable][] and -[Writable][] interfaces. - -Examples of Transform streams include: - -* [zlib streams][zlib] -* [crypto streams][crypto] - -### Class: stream.Writable - -<!--type=class--> - -The Writable stream interface is an abstraction for a *destination* -that you are writing data *to*. - -Examples of writable streams include: - -* [HTTP requests, on the client][] -* [HTTP responses, on the server][] -* [fs write streams][] -* [zlib streams][zlib] -* [crypto streams][crypto] -* [TCP sockets][] -* [child process stdin][] -* [`process.stdout`][], [`process.stderr`][] - -#### Event: 'drain' - -If a [`stream.write(chunk)`][stream-write] call returns `false`, then the -`'drain'` event will indicate when it is appropriate to begin writing more data -to the stream. - -```js -// Write the data to the supplied writable stream one million times. -// Be attentive to back-pressure. -function writeOneMillionTimes(writer, data, encoding, callback) { - var i = 1000000; - write(); - function write() { - var ok = true; - do { - i -= 1; - if (i === 0) { - // last time! - writer.write(data, encoding, callback); - } else { - // see if we should continue, or wait - // don't pass the callback, because we're not done yet. - ok = writer.write(data, encoding); - } - } while (i > 0 && ok); - if (i > 0) { - // had to stop early! - // write some more once it drains - writer.once('drain', write); - } - } -} -``` - -#### Event: 'error' - -* {Error} - -Emitted if there was an error when writing or piping data. - -#### Event: 'finish' - -When the [`stream.end()`][stream-end] method has been called, and all data has -been flushed to the underlying system, this event is emitted. - -```javascript -var writer = getWritableStreamSomehow(); -for (var i = 0; i < 100; i ++) { - writer.write('hello, #${i}!\n'); -} -writer.end('this is the end\n'); -writer.on('finish', () => { - console.error('all writes are now complete.'); -}); -``` - -#### Event: 'pipe' - -* `src` {stream.Readable} source stream that is piping to this writable - -This is emitted whenever the [`stream.pipe()`][] method is called on a readable -stream, adding this writable to its set of destinations. - -```js -var writer = getWritableStreamSomehow(); -var reader = getReadableStreamSomehow(); -writer.on('pipe', (src) => { - console.error('something is piping into the writer'); - assert.equal(src, reader); -}); -reader.pipe(writer); -``` - -#### Event: 'unpipe' - -* `src` {[Readable][] Stream} The source stream that - [unpiped][`stream.unpipe()`] this writable - -This is emitted whenever the [`stream.unpipe()`][] method is called on a -readable stream, removing this writable from its set of destinations. - -```js -var writer = getWritableStreamSomehow(); -var reader = getReadableStreamSomehow(); -writer.on('unpipe', (src) => { - console.error('something has stopped piping into the writer'); - assert.equal(src, reader); -}); -reader.pipe(writer); -reader.unpipe(writer); -``` - -#### writable.cork() - -Forces buffering of all writes. - -Buffered data will be flushed either at [`stream.uncork()`][] or at -[`stream.end()`][stream-end] call. - -#### writable.end([chunk][, encoding][, callback]) - -* `chunk` {String|Buffer} Optional data to write -* `encoding` {String} The encoding, if `chunk` is a String -* `callback` {Function} Optional callback for when the stream is finished - -Call this method when no more data will be written to the stream. If supplied, -the callback is attached as a listener on the [`'finish'`][] event. - -Calling [`stream.write()`][stream-write] after calling -[`stream.end()`][stream-end] will raise an error. - -```js -// write 'hello, ' and then end with 'world!' -var file = fs.createWriteStream('example.txt'); -file.write('hello, '); -file.end('world!'); -// writing more now is not allowed! -``` - -#### writable.setDefaultEncoding(encoding) - -* `encoding` {String} The new default encoding - -Sets the default encoding for a writable stream. - -#### writable.uncork() - -Flush all data, buffered since [`stream.cork()`][] call. - -#### writable.write(chunk[, encoding][, callback]) - -* `chunk` {String|Buffer} The data to write -* `encoding` {String} The encoding, if `chunk` is a String -* `callback` {Function} Callback for when this chunk of data is flushed -* Returns: {Boolean} `true` if the data was handled completely. - -This method writes some data to the underlying system, and calls the -supplied callback once the data has been fully handled. - -The return value indicates if you should continue writing right now. -If the data had to be buffered internally, then it will return -`false`. Otherwise, it will return `true`. - -This return value is strictly advisory. You MAY continue to write, -even if it returns `false`. However, writes will be buffered in -memory, so it is best not to do this excessively. Instead, wait for -the [`'drain'`][] event before writing more data. - - -## API for Stream Implementors - -<!--type=misc--> - -To implement any sort of stream, the pattern is the same: - -1. Extend the appropriate parent class in your own subclass. (The - [`util.inherits()`][] method is particularly helpful for this.) -2. Call the appropriate parent class constructor in your constructor, - to be sure that the internal mechanisms are set up properly. -3. Implement one or more specific methods, as detailed below. - -The class to extend and the method(s) to implement depend on the sort -of stream class you are writing: - -<table> - <thead> - <tr> - <th> - <p>Use-case</p> - </th> - <th> - <p>Class</p> - </th> - <th> - <p>Method(s) to implement</p> - </th> - </tr> - </thead> - <tr> - <td> - <p>Reading only</p> - </td> - <td> - <p>[Readable](#stream_class_stream_readable_1)</p> - </td> - <td> - <p><code>[_read][stream-_read]</code></p> - </td> - </tr> - <tr> - <td> - <p>Writing only</p> - </td> - <td> - <p>[Writable](#stream_class_stream_writable_1)</p> - </td> - <td> - <p><code>[_write][stream-_write]</code>, <code>[_writev][stream-_writev]</code></p> - </td> - </tr> - <tr> - <td> - <p>Reading and writing</p> - </td> - <td> - <p>[Duplex](#stream_class_stream_duplex_1)</p> - </td> - <td> - <p><code>[_read][stream-_read]</code>, <code>[_write][stream-_write]</code>, <code>[_writev][stream-_writev]</code></p> - </td> - </tr> - <tr> - <td> - <p>Operate on written data, then read the result</p> - </td> - <td> - <p>[Transform](#stream_class_stream_transform_1)</p> - </td> - <td> - <p><code>[_transform][stream-_transform]</code>, <code>[_flush][stream-_flush]</code></p> - </td> - </tr> -</table> - -In your implementation code, it is very important to never call the methods -described in [API for Stream Consumers][]. Otherwise, you can potentially cause -adverse side effects in programs that consume your streaming interfaces. - -### Class: stream.Duplex - -<!--type=class--> - -A "duplex" stream is one that is both Readable and Writable, such as a TCP -socket connection. - -Note that `stream.Duplex` is an abstract class designed to be extended -with an underlying implementation of the [`stream._read(size)`][stream-_read] -and [`stream._write(chunk, encoding, callback)`][stream-_write] methods as you -would with a Readable or Writable stream class. - -Since JavaScript doesn't have multiple prototypal inheritance, this class -prototypally inherits from Readable, and then parasitically from Writable. It is -thus up to the user to implement both the low-level -[`stream._read(n)`][stream-_read] method as well as the low-level -[`stream._write(chunk, encoding, callback)`][stream-_write] method on extension -duplex classes. - -#### new stream.Duplex(options) - -* `options` {Object} Passed to both Writable and Readable - constructors. Also has the following fields: - * `allowHalfOpen` {Boolean} Default = `true`. If set to `false`, then - the stream will automatically end the readable side when the - writable side ends and vice versa. - * `readableObjectMode` {Boolean} Default = `false`. Sets `objectMode` - for readable side of the stream. Has no effect if `objectMode` - is `true`. - * `writableObjectMode` {Boolean} Default = `false`. Sets `objectMode` - for writable side of the stream. Has no effect if `objectMode` - is `true`. - -In classes that extend the Duplex class, make sure to call the -constructor so that the buffering settings can be properly -initialized. - -### Class: stream.PassThrough - -This is a trivial implementation of a [Transform][] stream that simply -passes the input bytes across to the output. Its purpose is mainly -for examples and testing, but there are occasionally use cases where -it can come in handy as a building block for novel sorts of streams. - -### Class: stream.Readable - -<!--type=class--> - -`stream.Readable` is an abstract class designed to be extended with an -underlying implementation of the [`stream._read(size)`][stream-_read] method. - -Please see [API for Stream Consumers][] for how to consume -streams in your programs. What follows is an explanation of how to -implement Readable streams in your programs. - -#### new stream.Readable([options]) - -* `options` {Object} - * `highWaterMark` {Number} The maximum number of bytes to store in - the internal buffer before ceasing to read from the underlying - resource. Default = `16384` (16kb), or `16` for `objectMode` streams - * `encoding` {String} If specified, then buffers will be decoded to - strings using the specified encoding. Default = `null` - * `objectMode` {Boolean} Whether this stream should behave - as a stream of objects. Meaning that [`stream.read(n)`][stream-read] returns - a single value instead of a Buffer of size n. Default = `false` - * `read` {Function} Implementation for the [`stream._read()`][stream-_read] - method. - -In classes that extend the Readable class, make sure to call the -Readable constructor so that the buffering settings can be properly -initialized. - -#### readable.\_read(size) - -* `size` {Number} Number of bytes to read asynchronously - -Note: **Implement this method, but do NOT call it directly.** - -This method is prefixed with an underscore because it is internal to the -class that defines it and should only be called by the internal Readable -class methods. All Readable stream implementations must provide a \_read -method to fetch data from the underlying resource. - -When `_read()` is called, if data is available from the resource, the `_read()` -implementation should start pushing that data into the read queue by calling -[`this.push(dataChunk)`][stream-push]. `_read()` should continue reading from -the resource and pushing data until push returns `false`, at which point it -should stop reading from the resource. Only when `_read()` is called again after -it has stopped should it start reading more data from the resource and pushing -that data onto the queue. - -Note: once the `_read()` method is called, it will not be called again until -the [`stream.push()`][stream-push] method is called. - -The `size` argument is advisory. Implementations where a "read" is a -single call that returns data can use this to know how much data to -fetch. Implementations where that is not relevant, such as TCP or -TLS, may ignore this argument, and simply provide data whenever it -becomes available. There is no need, for example to "wait" until -`size` bytes are available before calling [`stream.push(chunk)`][stream-push]. - -#### readable.push(chunk[, encoding]) - - -* `chunk` {Buffer|Null|String} Chunk of data to push into the read queue -* `encoding` {String} Encoding of String chunks. Must be a valid - Buffer encoding, such as `'utf8'` or `'ascii'` -* return {Boolean} Whether or not more pushes should be performed - -Note: **This method should be called by Readable implementors, NOT -by consumers of Readable streams.** - -If a value other than null is passed, The `push()` method adds a chunk of data -into the queue for subsequent stream processors to consume. If `null` is -passed, it signals the end of the stream (EOF), after which no more data -can be written. - -The data added with `push()` can be pulled out by calling the -[`stream.read()`][stream-read] method when the [`'readable'`][] event fires. - -This API is designed to be as flexible as possible. For example, -you may be wrapping a lower-level source which has some sort of -pause/resume mechanism, and a data callback. In those cases, you -could wrap the low-level source object by doing something like this: - -```js -// source is an object with readStop() and readStart() methods, -// and an `ondata` member that gets called when it has data, and -// an `onend` member that gets called when the data is over. - -util.inherits(SourceWrapper, Readable); - -function SourceWrapper(options) { - Readable.call(this, options); - - this._source = getLowlevelSourceObject(); - - // Every time there's data, we push it into the internal buffer. - this._source.ondata = (chunk) => { - // if push() returns false, then we need to stop reading from source - if (!this.push(chunk)) - this._source.readStop(); - }; - - // When the source ends, we push the EOF-signaling `null` chunk - this._source.onend = () => { - this.push(null); - }; -} - -// _read will be called when the stream wants to pull more data in -// the advisory size argument is ignored in this case. -SourceWrapper.prototype._read = function(size) { - this._source.readStart(); -}; -``` - -#### Example: A Counting Stream - -<!--type=example--> - -This is a basic example of a Readable stream. It emits the numerals -from 1 to 1,000,000 in ascending order, and then ends. - -```js -const Readable = require('stream').Readable; -const util = require('util'); -util.inherits(Counter, Readable); - -function Counter(opt) { - Readable.call(this, opt); - this._max = 1000000; - this._index = 1; -} - -Counter.prototype._read = function() { - var i = this._index++; - if (i > this._max) - this.push(null); - else { - var str = '' + i; - var buf = new Buffer(str, 'ascii'); - this.push(buf); - } -}; -``` - -#### Example: SimpleProtocol v1 (Sub-optimal) - -This is similar to the `parseHeader` function described -[here](#stream_readable_unshift_chunk), but implemented as a custom stream. -Also, note that this implementation does not convert the incoming data to a -string. - -However, this would be better implemented as a [Transform][] stream. See -[SimpleProtocol v2][] for a better implementation. - -```js -// A parser for a simple data protocol. -// The "header" is a JSON object, followed by 2 \n characters, and -// then a message body. -// -// NOTE: This can be done more simply as a Transform stream! -// Using Readable directly for this is sub-optimal. See the -// alternative example below under the Transform section. - -const Readable = require('stream').Readable; -const util = require('util'); - -util.inherits(SimpleProtocol, Readable); - -function SimpleProtocol(source, options) { - if (!(this instanceof SimpleProtocol)) - return new SimpleProtocol(source, options); - - Readable.call(this, options); - this._inBody = false; - this._sawFirstCr = false; - - // source is a readable stream, such as a socket or file - this._source = source; - - var self = this; - source.on('end', () => { - self.push(null); - }); - - // give it a kick whenever the source is readable - // read(0) will not consume any bytes - source.on('readable', () => { - self.read(0); - }); - - this._rawHeader = []; - this.header = null; -} - -SimpleProtocol.prototype._read = function(n) { - if (!this._inBody) { - var chunk = this._source.read(); - - // if the source doesn't have data, we don't have data yet. - if (chunk === null) - return this.push(''); - - // check if the chunk has a \n\n - var split = -1; - for (var i = 0; i < chunk.length; i++) { - if (chunk[i] === 10) { // '\n' - if (this._sawFirstCr) { - split = i; - break; - } else { - this._sawFirstCr = true; - } - } else { - this._sawFirstCr = false; - } - } - - if (split === -1) { - // still waiting for the \n\n - // stash the chunk, and try again. - this._rawHeader.push(chunk); - this.push(''); - } else { - this._inBody = true; - var h = chunk.slice(0, split); - this._rawHeader.push(h); - var header = Buffer.concat(this._rawHeader).toString(); - try { - this.header = JSON.parse(header); - } catch (er) { - this.emit('error', new Error('invalid simple protocol data')); - return; - } - // now, because we got some extra data, unshift the rest - // back into the read queue so that our consumer will see it. - var b = chunk.slice(split); - this.unshift(b); - // calling unshift by itself does not reset the reading state - // of the stream; since we're inside _read, doing an additional - // push('') will reset the state appropriately. - this.push(''); - - // and let them know that we are done parsing the header. - this.emit('header', this.header); - } - } else { - // from there on, just provide the data to our consumer. - // careful not to push(null), since that would indicate EOF. - var chunk = this._source.read(); - if (chunk) this.push(chunk); - } -}; - -// Usage: -// var parser = new SimpleProtocol(source); -// Now parser is a readable stream that will emit 'header' -// with the parsed header data. -``` - -### Class: stream.Transform - -A "transform" stream is a duplex stream where the output is causally -connected in some way to the input, such as a [zlib][] stream or a -[crypto][] stream. - -There is no requirement that the output be the same size as the input, -the same number of chunks, or arrive at the same time. For example, a -Hash stream will only ever have a single chunk of output which is -provided when the input is ended. A zlib stream will produce output -that is either much smaller or much larger than its input. - -Rather than implement the [`stream._read()`][stream-_read] and -[`stream._write()`][stream-_write] methods, Transform classes must implement the -[`stream._transform()`][stream-_transform] method, and may optionally -also implement the [`stream._flush()`][stream-_flush] method. (See below.) - -#### new stream.Transform([options]) - -* `options` {Object} Passed to both Writable and Readable - constructors. Also has the following fields: - * `transform` {Function} Implementation for the - [`stream._transform()`][stream-_transform] method. - * `flush` {Function} Implementation for the [`stream._flush()`][stream-_flush] - method. - -In classes that extend the Transform class, make sure to call the -constructor so that the buffering settings can be properly -initialized. - -#### Events: 'finish' and 'end' - -The [`'finish'`][] and [`'end'`][] events are from the parent Writable -and Readable classes respectively. The `'finish'` event is fired after -[`stream.end()`][stream-end] is called and all chunks have been processed by -[`stream._transform()`][stream-_transform], `'end'` is fired after all data has -been output which is after the callback in [`stream._flush()`][stream-_flush] -has been called. - -#### transform.\_flush(callback) - -* `callback` {Function} Call this function (optionally with an error - argument) when you are done flushing any remaining data. - -Note: **This function MUST NOT be called directly.** It MAY be implemented -by child classes, and if so, will be called by the internal Transform -class methods only. - -In some cases, your transform operation may need to emit a bit more -data at the end of the stream. For example, a `Zlib` compression -stream will store up some internal state so that it can optimally -compress the output. At the end, however, it needs to do the best it -can with what is left, so that the data will be complete. - -In those cases, you can implement a `_flush()` method, which will be -called at the very end, after all the written data is consumed, but -before emitting [`'end'`][] to signal the end of the readable side. Just -like with [`stream._transform()`][stream-_transform], call -`transform.push(chunk)` zero or more times, as appropriate, and call `callback` -when the flush operation is complete. - -This method is prefixed with an underscore because it is internal to -the class that defines it, and should not be called directly by user -programs. However, you **are** expected to override this method in -your own extension classes. - -#### transform.\_transform(chunk, encoding, callback) - -* `chunk` {Buffer|String} The chunk to be transformed. Will **always** - be a buffer unless the `decodeStrings` option was set to `false`. -* `encoding` {String} If the chunk is a string, then this is the - encoding type. If chunk is a buffer, then this is the special - value - 'buffer', ignore it in this case. -* `callback` {Function} Call this function (optionally with an error - argument and data) when you are done processing the supplied chunk. - -Note: **This function MUST NOT be called directly.** It should be -implemented by child classes, and called by the internal Transform -class methods only. - -All Transform stream implementations must provide a `_transform()` -method to accept input and produce output. - -`_transform()` should do whatever has to be done in this specific -Transform class, to handle the bytes being written, and pass them off -to the readable portion of the interface. Do asynchronous I/O, -process things, and so on. - -Call `transform.push(outputChunk)` 0 or more times to generate output -from this input chunk, depending on how much data you want to output -as a result of this chunk. - -Call the callback function only when the current chunk is completely -consumed. Note that there may or may not be output as a result of any -particular input chunk. If you supply a second argument to the callback -it will be passed to the push method. In other words the following are -equivalent: - -```js -transform.prototype._transform = function (data, encoding, callback) { - this.push(data); - callback(); -}; - -transform.prototype._transform = function (data, encoding, callback) { - callback(null, data); -}; -``` - -This method is prefixed with an underscore because it is internal to -the class that defines it, and should not be called directly by user -programs. However, you **are** expected to override this method in -your own extension classes. - -#### Example: `SimpleProtocol` parser v2 - -The example [here](#stream_example_simpleprotocol_v1_sub_optimal) of a simple -protocol parser can be implemented simply by using the higher level -[Transform][] stream class, similar to the `parseHeader` and `SimpleProtocol -v1` examples. - -In this example, rather than providing the input as an argument, it -would be piped into the parser, which is a more idiomatic Node.js stream -approach. - -```javascript -const util = require('util'); -const Transform = require('stream').Transform; -util.inherits(SimpleProtocol, Transform); - -function SimpleProtocol(options) { - if (!(this instanceof SimpleProtocol)) - return new SimpleProtocol(options); - - Transform.call(this, options); - this._inBody = false; - this._sawFirstCr = false; - this._rawHeader = []; - this.header = null; -} - -SimpleProtocol.prototype._transform = function(chunk, encoding, done) { - if (!this._inBody) { - // check if the chunk has a \n\n - var split = -1; - for (var i = 0; i < chunk.length; i++) { - if (chunk[i] === 10) { // '\n' - if (this._sawFirstCr) { - split = i; - break; - } else { - this._sawFirstCr = true; - } - } else { - this._sawFirstCr = false; - } - } - - if (split === -1) { - // still waiting for the \n\n - // stash the chunk, and try again. - this._rawHeader.push(chunk); - } else { - this._inBody = true; - var h = chunk.slice(0, split); - this._rawHeader.push(h); - var header = Buffer.concat(this._rawHeader).toString(); - try { - this.header = JSON.parse(header); - } catch (er) { - this.emit('error', new Error('invalid simple protocol data')); - return; - } - // and let them know that we are done parsing the header. - this.emit('header', this.header); - - // now, because we got some extra data, emit this first. - this.push(chunk.slice(split)); - } - } else { - // from there on, just provide the data to our consumer as-is. - this.push(chunk); - } - done(); -}; - -// Usage: -// var parser = new SimpleProtocol(); -// source.pipe(parser) -// Now parser is a readable stream that will emit 'header' -// with the parsed header data. -``` - -### Class: stream.Writable - -<!--type=class--> - -`stream.Writable` is an abstract class designed to be extended with an -underlying implementation of the -[`stream._write(chunk, encoding, callback)`][stream-_write] method. - -Please see [API for Stream Consumers][] for how to consume -writable streams in your programs. What follows is an explanation of -how to implement Writable streams in your programs. - -#### new stream.Writable([options]) - -* `options` {Object} - * `highWaterMark` {Number} Buffer level when - [`stream.write()`][stream-write] starts returning `false`. Default = `16384` - (16kb), or `16` for `objectMode` streams. - * `decodeStrings` {Boolean} Whether or not to decode strings into - Buffers before passing them to [`stream._write()`][stream-_write]. - Default = `true` - * `objectMode` {Boolean} Whether or not the - [`stream.write(anyObj)`][stream-write] is a valid operation. If set you can - write arbitrary data instead of only `Buffer` / `String` data. - Default = `false` - * `write` {Function} Implementation for the - [`stream._write()`][stream-_write] method. - * `writev` {Function} Implementation for the - [`stream._writev()`][stream-_writev] method. - -In classes that extend the Writable class, make sure to call the -constructor so that the buffering settings can be properly -initialized. - -#### writable.\_write(chunk, encoding, callback) - -* `chunk` {Buffer|String} The chunk to be written. Will **always** - be a buffer unless the `decodeStrings` option was set to `false`. -* `encoding` {String} If the chunk is a string, then this is the - encoding type. If chunk is a buffer, then this is the special - value - 'buffer', ignore it in this case. -* `callback` {Function} Call this function (optionally with an error - argument) when you are done processing the supplied chunk. - -All Writable stream implementations must provide a -[`stream._write()`][stream-_write] method to send data to the underlying -resource. - -Note: **This function MUST NOT be called directly.** It should be -implemented by child classes, and called by the internal Writable -class methods only. - -Call the callback using the standard `callback(error)` pattern to -signal that the write completed successfully or with an error. - -If the `decodeStrings` flag is set in the constructor options, then -`chunk` may be a string rather than a Buffer, and `encoding` will -indicate the sort of string that it is. This is to support -implementations that have an optimized handling for certain string -data encodings. If you do not explicitly set the `decodeStrings` -option to `false`, then you can safely ignore the `encoding` argument, -and assume that `chunk` will always be a Buffer. - -This method is prefixed with an underscore because it is internal to -the class that defines it, and should not be called directly by user -programs. However, you **are** expected to override this method in -your own extension classes. - -#### writable.\_writev(chunks, callback) - -* `chunks` {Array} The chunks to be written. Each chunk has following - format: `{ chunk: ..., encoding: ... }`. -* `callback` {Function} Call this function (optionally with an error - argument) when you are done processing the supplied chunks. - -Note: **This function MUST NOT be called directly.** It may be -implemented by child classes, and called by the internal Writable -class methods only. - -This function is completely optional to implement. In most cases it is -unnecessary. If implemented, it will be called with all the chunks -that are buffered in the write queue. - - -## Simplified Constructor API - -<!--type=misc--> - -In simple cases there is now the added benefit of being able to construct a -stream without inheritance. - -This can be done by passing the appropriate methods as constructor options: - -Examples: - -### Duplex - -```js -var duplex = new stream.Duplex({ - read: function(n) { - // sets this._read under the hood - - // push data onto the read queue, passing null - // will signal the end of the stream (EOF) - this.push(chunk); - }, - write: function(chunk, encoding, next) { - // sets this._write under the hood - - // An optional error can be passed as the first argument - next() - } -}); - -// or - -var duplex = new stream.Duplex({ - read: function(n) { - // sets this._read under the hood - - // push data onto the read queue, passing null - // will signal the end of the stream (EOF) - this.push(chunk); - }, - writev: function(chunks, next) { - // sets this._writev under the hood - - // An optional error can be passed as the first argument - next() - } -}); -``` - -### Readable - -```js -var readable = new stream.Readable({ - read: function(n) { - // sets this._read under the hood - - // push data onto the read queue, passing null - // will signal the end of the stream (EOF) - this.push(chunk); - } -}); -``` - -### Transform - -```js -var transform = new stream.Transform({ - transform: function(chunk, encoding, next) { - // sets this._transform under the hood - - // generate output as many times as needed - // this.push(chunk); - - // call when the current chunk is consumed - next(); - }, - flush: function(done) { - // sets this._flush under the hood - - // generate output as many times as needed - // this.push(chunk); - - done(); - } -}); -``` - -### Writable - -```js -var writable = new stream.Writable({ - write: function(chunk, encoding, next) { - // sets this._write under the hood - - // An optional error can be passed as the first argument - next() - } -}); - -// or - -var writable = new stream.Writable({ - writev: function(chunks, next) { - // sets this._writev under the hood - - // An optional error can be passed as the first argument - next() - } -}); -``` - -## Streams: Under the Hood - -<!--type=misc--> - -### Buffering - -<!--type=misc--> - -Both Writable and Readable streams will buffer data on an internal -object which can be retrieved from `_writableState.getBuffer()` or -`_readableState.buffer`, respectively. - -The amount of data that will potentially be buffered depends on the -`highWaterMark` option which is passed into the constructor. - -Buffering in Readable streams happens when the implementation calls -[`stream.push(chunk)`][stream-push]. If the consumer of the Stream does not -call [`stream.read()`][stream-read], then the data will sit in the internal -queue until it is consumed. - -Buffering in Writable streams happens when the user calls -[`stream.write(chunk)`][stream-write] repeatedly, even when it returns `false`. - -The purpose of streams, especially with the [`stream.pipe()`][] method, is to -limit the buffering of data to acceptable levels, so that sources and -destinations of varying speed will not overwhelm the available memory. - -### Compatibility with Older Node.js Versions - -<!--type=misc--> - -In versions of Node.js prior to v0.10, the Readable stream interface was -simpler, but also less powerful and less useful. - -* Rather than waiting for you to call the [`stream.read()`][stream-read] method, - [`'data'`][] events would start emitting immediately. If you needed to do - some I/O to decide how to handle data, then you had to store the chunks - in some kind of buffer so that they would not be lost. -* The [`stream.pause()`][stream-pause] method was advisory, rather than - guaranteed. This meant that you still had to be prepared to receive - [`'data'`][] events even when the stream was in a paused state. - -In Node.js v0.10, the [Readable][] class was added. -For backwards compatibility with older Node.js programs, Readable streams -switch into "flowing mode" when a [`'data'`][] event handler is added, or -when the [`stream.resume()`][stream-resume] method is called. The effect is -that, even if you are not using the new [`stream.read()`][stream-read] method -and [`'readable'`][] event, you no longer have to worry about losing -[`'data'`][] chunks. - -Most programs will continue to function normally. However, this -introduces an edge case in the following conditions: - -* No [`'data'`][] event handler is added. -* The [`stream.resume()`][stream-resume] method is never called. -* The stream is not piped to any writable destination. - -For example, consider the following code: - -```js -// WARNING! BROKEN! -net.createServer((socket) => { - - // we add an 'end' method, but never consume the data - socket.on('end', () => { - // It will never get here. - socket.end('I got your message (but didnt read it)\n'); - }); - -}).listen(1337); -``` - -In versions of Node.js prior to v0.10, the incoming message data would be -simply discarded. However, in Node.js v0.10 and beyond, -the socket will remain paused forever. - -The workaround in this situation is to call the -[`stream.resume()`][stream-resume] method to start the flow of data: - -```js -// Workaround -net.createServer((socket) => { - - socket.on('end', () => { - socket.end('I got your message (but didnt read it)\n'); - }); - - // start the flow of data, discarding it. - socket.resume(); - -}).listen(1337); -``` - -In addition to new Readable streams switching into flowing mode, -pre-v0.10 style streams can be wrapped in a Readable class using the -[`stream.wrap()`][] method. - - -### Object Mode - -<!--type=misc--> - -Normally, Streams operate on Strings and Buffers exclusively. - -Streams that are in **object mode** can emit generic JavaScript values -other than Buffers and Strings. - -A Readable stream in object mode will always return a single item from -a call to [`stream.read(size)`][stream-read], regardless of what the size -argument is. - -A Writable stream in object mode will always ignore the `encoding` -argument to [`stream.write(data, encoding)`][stream-write]. - -The special value `null` still retains its special value for object -mode streams. That is, for object mode readable streams, `null` as a -return value from [`stream.read()`][stream-read] indicates that there is no more -data, and [`stream.push(null)`][stream-push] will signal the end of stream data -(`EOF`). - -No streams in Node.js core are object mode streams. This pattern is only -used by userland streaming libraries. - -You should set `objectMode` in your stream child class constructor on -the options object. Setting `objectMode` mid-stream is not safe. - -For Duplex streams `objectMode` can be set exclusively for readable or -writable side with `readableObjectMode` and `writableObjectMode` -respectively. These options can be used to implement parsers and -serializers with Transform streams. - -```js -const util = require('util'); -const StringDecoder = require('string_decoder').StringDecoder; -const Transform = require('stream').Transform; -util.inherits(JSONParseStream, Transform); - -// Gets \n-delimited JSON string data, and emits the parsed objects -function JSONParseStream() { - if (!(this instanceof JSONParseStream)) - return new JSONParseStream(); - - Transform.call(this, { readableObjectMode : true }); - - this._buffer = ''; - this._decoder = new StringDecoder('utf8'); -} - -JSONParseStream.prototype._transform = function(chunk, encoding, cb) { - this._buffer += this._decoder.write(chunk); - // split on newlines - var lines = this._buffer.split(/\r?\n/); - // keep the last partial line buffered - this._buffer = lines.pop(); - for (var l = 0; l < lines.length; l++) { - var line = lines[l]; - try { - var obj = JSON.parse(line); - } catch (er) { - this.emit('error', er); - return; - } - // push the parsed object out to the readable consumer - this.push(obj); - } - cb(); -}; - -JSONParseStream.prototype._flush = function(cb) { - // Just handle any leftover - var rem = this._buffer.trim(); - if (rem) { - try { - var obj = JSON.parse(rem); - } catch (er) { - this.emit('error', er); - return; - } - // push the parsed object out to the readable consumer - this.push(obj); - } - cb(); -}; -``` - -### `stream.read(0)` - -There are some cases where you want to trigger a refresh of the -underlying readable stream mechanisms, without actually consuming any -data. In that case, you can call `stream.read(0)`, which will always -return null. - -If the internal read buffer is below the `highWaterMark`, and the -stream is not currently reading, then calling `stream.read(0)` will trigger -a low-level [`stream._read()`][stream-_read] call. - -There is almost never a need to do this. However, you will see some -cases in Node.js's internals where this is done, particularly in the -Readable stream class internals. - -### `stream.push('')` - -Pushing a zero-byte string or Buffer (when not in [Object mode][]) has an -interesting side effect. Because it *is* a call to -[`stream.push()`][stream-push], it will end the `reading` process. However, it -does *not* add any data to the readable buffer, so there's nothing for -a user to consume. - -Very rarely, there are cases where you have no data to provide now, -but the consumer of your stream (or, perhaps, another bit of your own -code) will know when to check again, by calling [`stream.read(0)`][stream-read]. -In those cases, you *may* call `stream.push('')`. - -So far, the only use case for this functionality is in the -[`tls.CryptoStream`][] class, which is deprecated in Node.js/io.js v1.0. If you -find that you have to use `stream.push('')`, please consider another -approach, because it almost certainly indicates that something is -horribly wrong. - -[`'data'`]: #stream_event_data -[`'drain'`]: #stream_event_drain -[`'end'`]: #stream_event_end -[`'finish'`]: #stream_event_finish -[`'readable'`]: #stream_event_readable -[`buf.toString(encoding)`]: https://nodejs.org/docs/v5.8.0/api/buffer.html#buffer_buf_tostring_encoding_start_end -[`EventEmitter`]: https://nodejs.org/docs/v5.8.0/api/events.html#events_class_eventemitter -[`process.stderr`]: https://nodejs.org/docs/v5.8.0/api/process.html#process_process_stderr -[`process.stdin`]: https://nodejs.org/docs/v5.8.0/api/process.html#process_process_stdin -[`process.stdout`]: https://nodejs.org/docs/v5.8.0/api/process.html#process_process_stdout -[`stream.cork()`]: #stream_writable_cork -[`stream.pipe()`]: #stream_readable_pipe_destination_options -[`stream.uncork()`]: #stream_writable_uncork -[`stream.unpipe()`]: #stream_readable_unpipe_destination -[`stream.wrap()`]: #stream_readable_wrap_stream -[`tls.CryptoStream`]: https://nodejs.org/docs/v5.8.0/api/tls.html#tls_class_cryptostream -[`util.inherits()`]: https://nodejs.org/docs/v5.8.0/api/util.html#util_util_inherits_constructor_superconstructor -[API for Stream Consumers]: #stream_api_for_stream_consumers -[API for Stream Implementors]: #stream_api_for_stream_implementors -[child process stdin]: https://nodejs.org/docs/v5.8.0/api/child_process.html#child_process_child_stdin -[child process stdout and stderr]: https://nodejs.org/docs/v5.8.0/api/child_process.html#child_process_child_stdout -[Compatibility]: #stream_compatibility_with_older_node_js_versions -[crypto]: crypto.html -[Duplex]: #stream_class_stream_duplex -[fs read streams]: https://nodejs.org/docs/v5.8.0/api/fs.html#fs_class_fs_readstream -[fs write streams]: https://nodejs.org/docs/v5.8.0/api/fs.html#fs_class_fs_writestream -[HTTP requests, on the client]: https://nodejs.org/docs/v5.8.0/api/http.html#http_class_http_clientrequest -[HTTP responses, on the server]: https://nodejs.org/docs/v5.8.0/api/http.html#http_class_http_serverresponse -[http-incoming-message]: https://nodejs.org/docs/v5.8.0/api/http.html#http_class_http_incomingmessage -[Object mode]: #stream_object_mode -[Readable]: #stream_class_stream_readable -[SimpleProtocol v2]: #stream_example_simpleprotocol_parser_v2 -[stream-_flush]: #stream_transform_flush_callback -[stream-_read]: #stream_readable_read_size_1 -[stream-_transform]: #stream_transform_transform_chunk_encoding_callback -[stream-_write]: #stream_writable_write_chunk_encoding_callback_1 -[stream-_writev]: #stream_writable_writev_chunks_callback -[stream-end]: #stream_writable_end_chunk_encoding_callback -[stream-pause]: #stream_readable_pause -[stream-push]: #stream_readable_push_chunk_encoding -[stream-read]: #stream_readable_read_size -[stream-resume]: #stream_readable_resume -[stream-write]: #stream_writable_write_chunk_encoding_callback -[TCP sockets]: https://nodejs.org/docs/v5.8.0/api/net.html#net_class_net_socket -[Transform]: #stream_class_stream_transform -[Writable]: #stream_class_stream_writable -[zlib]: zlib.html |