[英]Zipping two readable streams does not seem to produce anything
I have the following function: 我有以下功能:
const _ = require('highland');
module.exports =
(numbers /* Readable */, words /* Readable */, repeated_words /* Writable */) => {
const numberStream = _(numbers);
const wordStream = _(words);
numberStream
.zip(wordStream)
.flatMap((numberWordPair) => {
const result = [];
for (let i = 0; i < numberWordPair[0]; i++) {
result.push(numberWordPair[1]);
}
return _(result);
})
.pipe(repeated_words);
};
The stream arguments are automatically injected and I am 100% sure the stream injection works (other streaming functions work). 流参数是自动注入的,我100%确定流注入有效(其他流函数有效)。
When I replace this somewhat complex transformation by something as straightforward as _(numbers).each(xs => {console.log(xs)})
, I can see the data being logged. 当我用
_(numbers).each(xs => {console.log(xs)})
简单明了的东西替换这个有点复杂的转换时,我可以看到正在记录的数据。
However, here, I must be clearly missing something with Highland.js as there is nothing produced at all. 但是,在这里, Highland.js必须明显缺少一些东西,因为根本没有产生任何东西。
I'm using version 2.13.5 of Highland.js. 我正在使用Highland.js 2.13.5版本。
What am I missing? 我想念什么?
It appears it all works properly, therefore the mistake must lie somewhere else. 看来一切正常,因此错误必须出在其他地方。 As a proof, I was able to run this little program:
作为证明,我能够运行以下小程序:
const {TextDecoder} = require('util');
const repeater = require('./lib/repeater');
const {PassThrough, Readable, Transform} = require('stream');
class ConstantSource extends Readable {
constructor(options, constant) {
super(options);
this.constant = constant;
}
_read(size) {
for (let i = 0; i < size; i++) {
this.push(this.constant);
}
}
}
class StdinSource extends Readable {
constructor(options) {
super(options);
this.decoder = new TextDecoder('utf8');
process.stdin.on('data', (chunk) => {
this.push(this.decoder.decode(chunk).trim());
});
}
_read(size) {
}
}
class StdoutSink extends Transform {
constructor(options) {
super(options);
this.pipe(process.stdout);
}
_transform(chunk, _, callback) {
callback(null, '\x1b[33m' + chunk + '\x1b[0m\n');
}
}
const main = () => {
if (process.argv.length < 3) {
console.error('Please specify a number.');
process.exit(1);
}
const options = {objectMode: true};
const inputStream1 = new ConstantSource(options, process.argv[2]);
const inputStream2 = new StdinSource(options);
const outputStream = new StdoutSink(options);
repeater(inputStream1, inputStream2, outputStream);
}
main();
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