mirror of
https://github.com/denoland/deno.git
synced 2024-12-27 01:29:14 -05:00
111 lines
3.8 KiB
JavaScript
111 lines
3.8 KiB
JavaScript
// deno-fmt-ignore-file
|
|
// deno-lint-ignore-file
|
|
|
|
// Copyright Joyent and Node contributors. All rights reserved. MIT license.
|
|
// Taken from Node 18.12.1
|
|
// This file is automatically generated by `tools/node_compat/setup.ts`. Do not modify this file manually.
|
|
|
|
'use strict';
|
|
|
|
const common = require('../common');
|
|
|
|
// Ensure that subscribing the 'data' event will not make the stream flow.
|
|
// The 'data' event will require calling read() by hand.
|
|
//
|
|
// The test is written for the (somewhat rare) highWaterMark: 0 streams to
|
|
// specifically catch any regressions that might occur with these streams.
|
|
|
|
const assert = require('assert');
|
|
const { Readable } = require('stream');
|
|
|
|
const streamData = [ 'a', null ];
|
|
|
|
// Track the calls so we can assert their order later.
|
|
const calls = [];
|
|
const r = new Readable({
|
|
read: common.mustCall(() => {
|
|
calls.push('_read:' + streamData[0]);
|
|
process.nextTick(() => {
|
|
calls.push('push:' + streamData[0]);
|
|
r.push(streamData.shift());
|
|
});
|
|
}, streamData.length),
|
|
highWaterMark: 0,
|
|
|
|
// Object mode is used here just for testing convenience. It really
|
|
// shouldn't affect the order of events. Just the data and its format.
|
|
objectMode: true,
|
|
});
|
|
|
|
assert.strictEqual(r.readableFlowing, null);
|
|
r.on('readable', common.mustCall(() => {
|
|
calls.push('readable');
|
|
}, 2));
|
|
assert.strictEqual(r.readableFlowing, false);
|
|
r.on('data', common.mustCall((data) => {
|
|
calls.push('data:' + data);
|
|
}, 1));
|
|
r.on('end', common.mustCall(() => {
|
|
calls.push('end');
|
|
}));
|
|
assert.strictEqual(r.readableFlowing, false);
|
|
|
|
// The stream emits the events asynchronously but that's not guaranteed to
|
|
// happen on the next tick (especially since the _read implementation above
|
|
// uses process.nextTick).
|
|
//
|
|
// We use setImmediate here to give the stream enough time to emit all the
|
|
// events it's about to emit.
|
|
setImmediate(() => {
|
|
|
|
// Only the _read, push, readable calls have happened. No data must be
|
|
// emitted yet.
|
|
assert.deepStrictEqual(calls, ['_read:a', 'push:a', 'readable']);
|
|
|
|
// Calling 'r.read()' should trigger the data event.
|
|
assert.strictEqual(r.read(), 'a');
|
|
assert.deepStrictEqual(
|
|
calls,
|
|
['_read:a', 'push:a', 'readable', 'data:a']);
|
|
|
|
// The next 'read()' will return null because hwm: 0 does not buffer any
|
|
// data and the _read implementation above does the push() asynchronously.
|
|
//
|
|
// Note: This 'null' signals "no data available". It isn't the end-of-stream
|
|
// null value as the stream doesn't know yet that it is about to reach the
|
|
// end.
|
|
//
|
|
// Using setImmediate again to give the stream enough time to emit all the
|
|
// events it wants to emit.
|
|
assert.strictEqual(r.read(), null);
|
|
setImmediate(() => {
|
|
|
|
// There's a new 'readable' event after the data has been pushed.
|
|
// The 'end' event will be emitted only after a 'read()'.
|
|
//
|
|
// This is somewhat special for the case where the '_read' implementation
|
|
// calls 'push' asynchronously. If 'push' was synchronous, the 'end' event
|
|
// would be emitted here _before_ we call read().
|
|
assert.deepStrictEqual(
|
|
calls,
|
|
['_read:a', 'push:a', 'readable', 'data:a',
|
|
'_read:null', 'push:null', 'readable']);
|
|
|
|
assert.strictEqual(r.read(), null);
|
|
|
|
// While it isn't really specified whether the 'end' event should happen
|
|
// synchronously with read() or not, we'll assert the current behavior
|
|
// ('end' event happening on the next tick after read()) so any changes
|
|
// to it are noted and acknowledged in the future.
|
|
assert.deepStrictEqual(
|
|
calls,
|
|
['_read:a', 'push:a', 'readable', 'data:a',
|
|
'_read:null', 'push:null', 'readable']);
|
|
process.nextTick(() => {
|
|
assert.deepStrictEqual(
|
|
calls,
|
|
['_read:a', 'push:a', 'readable', 'data:a',
|
|
'_read:null', 'push:null', 'readable', 'end']);
|
|
});
|
|
});
|
|
});
|