Files
strom/src/functions/merge.ts
2019-09-09 15:58:35 -04:00

34 lines
1.1 KiB
TypeScript

import { Readable } from "stream";
export function merge(...streams: Readable[]): Readable {
let isStarted = false;
let streamEndedCount = 0;
return new Readable({
objectMode: true,
read() {
if (streamEndedCount >= streams.length) {
this.push(null);
} else if (!isStarted) {
isStarted = true;
streams.forEach(stream =>
stream
.on("data", chunk => {
if (!this.push(chunk)) {
streams.forEach(s => s.pause());
}
})
.on("error", err => this.emit("error", err))
.on("end", () => {
streamEndedCount++;
if (streamEndedCount === streams.length) {
this.push(null);
}
}),
);
} else {
streams.forEach(s => s.resume());
}
},
});
}