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

38 lines
1.1 KiB
TypeScript

import { Readable } from "stream";
export function concat(...streams: NodeJS.ReadableStream[]): Readable {
let isStarted = false;
let currentStreamIndex = 0;
const startCurrentStream = () => {
if (currentStreamIndex >= streams.length) {
wrapper.push(null);
} else {
streams[currentStreamIndex]
.on("data", chunk => {
if (!wrapper.push(chunk)) {
streams[currentStreamIndex].pause();
}
})
.on("error", err => wrapper.emit("error", err))
.on("end", () => {
currentStreamIndex++;
startCurrentStream();
});
}
};
const wrapper = new Readable({
objectMode: true,
read() {
if (!isStarted) {
isStarted = true;
startCurrentStream();
}
if (currentStreamIndex < streams.length) {
streams[currentStreamIndex].resume();
}
},
});
return wrapper;
}