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'use strict';
require('../common');
const assert = require('assert');
const stream = require('stream');
const Writable = stream.Writable;
// Test the buffering behavior of Writable streams.
//
// The call to cork() triggers storing chunks which are flushed
// on calling uncork() in the same tick.
//
// node version target: 0.12
const expectedChunks = ['please', 'buffer', 'me', 'kindly'];
const inputChunks = expectedChunks.slice(0);
let seenChunks = [];
let seenEnd = false;
const w = new Writable();
// lets arrange to store the chunks
w._write = function(chunk, encoding, cb) {
// default encoding given none was specified
assert.strictEqual(encoding, 'buffer');
seenChunks.push(chunk);
cb();
};
// lets record the stream end event
w.on('finish', () => {
seenEnd = true;
});
function writeChunks(remainingChunks, callback) {
const writeChunk = remainingChunks.shift();
let writeState;
if (writeChunk) {
setImmediate(() => {
writeState = w.write(writeChunk);
// we were not told to stop writing
assert.ok(writeState);
writeChunks(remainingChunks, callback);
});
} else {
callback();
}
}
// do an initial write
w.write('stuff');
// the write was immediate
assert.strictEqual(seenChunks.length, 1);
// reset the chunks seen so far
seenChunks = [];
// trigger stream buffering
w.cork();
// write the bufferedChunks
writeChunks(inputChunks, () => {
// should not have seen anything yet
assert.strictEqual(seenChunks.length, 0);
// trigger writing out the buffer
w.uncork();
// buffered bytes should be seen in current tick
assert.strictEqual(seenChunks.length, 4);
// did the chunks match
for (let i = 0, l = expectedChunks.length; i < l; i++) {
const seen = seenChunks[i];
// there was a chunk
assert.ok(seen);
const expected = Buffer.from(expectedChunks[i]);
// it was what we expected
assert.ok(seen.equals(expected));
}
setImmediate(() => {
// the stream should not have been ended
assert.ok(!seenEnd);
});
});
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