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ba513d140c
Adds the ability to for write streams to have an _final method which acts similarly to the _flush method that transform streams have but is called before the finish event is emitted and if asynchronous delays the stream from finishing. The `final` option may also be passed in order to set it. PR-URL: https://github.com/nodejs/node/pull/12828 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Refael Ackermann <refack@gmail.com>
101 lines
2.3 KiB
JavaScript
101 lines
2.3 KiB
JavaScript
'use strict';
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const common = require('../common');
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const assert = require('assert');
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const stream = require('stream');
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let state = 0;
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/*
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What you do
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var stream = new tream.Transform({
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transform: function transformCallback(chunk, _, next) {
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// part 1
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this.push(chunk);
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//part 2
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next();
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},
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final: function endCallback(done) {
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// part 1
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process.nextTick(function () {
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// part 2
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done();
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});
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},
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flush: function flushCallback(done) {
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// part 1
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process.nextTick(function () {
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// part 2
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done();
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});
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}
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});
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t.on('data', dataListener);
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t.on('end', endListener);
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t.on('finish', finishListener);
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t.write(1);
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t.write(4);
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t.end(7, endMethodCallback);
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The order things are called
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1. transformCallback part 1
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2. dataListener
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3. transformCallback part 2
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4. transformCallback part 1
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5. dataListener
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6. transformCallback part 2
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7. transformCallback part 1
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8. dataListener
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9. transformCallback part 2
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10. finalCallback part 1
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11. finalCallback part 2
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12. flushCallback part 1
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13. finishListener
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14. endMethodCallback
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15. flushCallback part 2
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16. endListener
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*/
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const t = new stream.Transform({
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objectMode: true,
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transform: common.mustCall(function(chunk, _, next) {
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assert.strictEqual(++state, chunk, 'transformCallback part 1');
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this.push(state);
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assert.strictEqual(++state, chunk + 2, 'transformCallback part 2');
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process.nextTick(next);
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}, 3),
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final: common.mustCall(function(done) {
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state++;
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assert.strictEqual(state, 10, 'finalCallback part 1');
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state++;
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assert.strictEqual(state, 11, 'finalCallback part 2');
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done();
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}, 1),
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flush: common.mustCall(function(done) {
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state++;
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assert.strictEqual(state, 12, 'flushCallback part 1');
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process.nextTick(function() {
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state++;
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assert.strictEqual(state, 15, 'flushCallback part 2');
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done();
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});
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}, 1)
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});
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t.on('finish', common.mustCall(function() {
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state++;
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assert.strictEqual(state, 13, 'finishListener');
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}, 1));
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t.on('end', common.mustCall(function() {
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state++;
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assert.strictEqual(state, 16, 'end event');
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}, 1));
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t.on('data', common.mustCall(function(d) {
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assert.strictEqual(++state, d + 1, 'dataListener');
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}, 3));
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t.write(1);
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t.write(4);
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t.end(7, common.mustCall(function() {
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state++;
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assert.strictEqual(state, 14, 'endMethodCallback');
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}, 1));
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