57 lines
1.3 KiB
TypeScript
57 lines
1.3 KiB
TypeScript
import { tap, expect } from '@push.rocks/tapbundle';
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import { SmartDuplex } from '../ts/index.js';
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tap.test('Backpressure: should apply backpressure across piped streams', async (toolsArg) => {
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const done = toolsArg.defer();
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const stream1 = new SmartDuplex({
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name: 'stream1',
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objectMode: true,
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writeFunction: async (chunk, tools) => {
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await new Promise((resolve) => setTimeout(resolve, 10));
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return chunk;
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},
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});
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const stream2 = new SmartDuplex({
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name: 'stream2',
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objectMode: true,
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writeFunction: async (chunk, tools) => {
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await new Promise((resolve) => setTimeout(resolve, 20));
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await tools.push(chunk);
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},
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});
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const stream3 = new SmartDuplex({
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objectMode: true,
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name: 'stream3',
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writeFunction: async (chunk, tools) => {
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await new Promise((resolve) => setTimeout(resolve, 200));
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},
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});
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stream1.pipe(stream2).pipe(stream3);
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let backpressured = false;
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for (let i = 0; i < 200; i++) {
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const canContinue = stream1.write(`Chunk ${i}`, 'utf8');
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if (!canContinue) {
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backpressured = true;
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}
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}
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stream1.end();
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stream3.on('finish', () => {
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if (!backpressured) {
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throw new Error('No backpressure was observed.');
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} else {
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done.resolve();
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}
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});
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await done.promise;
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});
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export default tap.start();
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