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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();
// Let's 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();
};
// Let's 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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