nodejs-mozilla/test/parallel/test-stream-pipe-flow.js

91 lines
1.9 KiB
JavaScript

'use strict';
const common = require('../common');
const assert = require('assert');
const { Readable, Writable, PassThrough } = require('stream');
{
let ticks = 17;
const rs = new Readable({
objectMode: true,
read: () => {
if (ticks-- > 0)
return process.nextTick(() => rs.push({}));
rs.push({});
rs.push(null);
}
});
const ws = new Writable({
highWaterMark: 0,
objectMode: true,
write: (data, end, cb) => setImmediate(cb)
});
rs.on('end', common.mustCall());
ws.on('finish', common.mustCall());
rs.pipe(ws);
}
{
let missing = 8;
const rs = new Readable({
objectMode: true,
read: () => {
if (missing--) rs.push({});
else rs.push(null);
}
});
const pt = rs
.pipe(new PassThrough({ objectMode: true, highWaterMark: 2 }))
.pipe(new PassThrough({ objectMode: true, highWaterMark: 2 }));
pt.on('end', () => {
wrapper.push(null);
});
const wrapper = new Readable({
objectMode: true,
read: () => {
process.nextTick(() => {
let data = pt.read();
if (data === null) {
pt.once('readable', () => {
data = pt.read();
if (data !== null) wrapper.push(data);
});
} else {
wrapper.push(data);
}
});
}
});
wrapper.resume();
wrapper.on('end', common.mustCall());
}
{
// Only register drain if there is backpressure.
const rs = new Readable({ read() {} });
const pt = rs
.pipe(new PassThrough({ objectMode: true, highWaterMark: 2 }));
assert.strictEqual(pt.listenerCount('drain'), 0);
pt.on('finish', () => {
assert.strictEqual(pt.listenerCount('drain'), 0);
});
rs.push('asd');
assert.strictEqual(pt.listenerCount('drain'), 0);
process.nextTick(() => {
rs.push('asd');
assert.strictEqual(pt.listenerCount('drain'), 0);
rs.push(null);
assert.strictEqual(pt.listenerCount('drain'), 0);
});
}