@techmely/utils/mergeStreams.js

Collection of helpful JavaScript / TypeScript utils

/*!
 * @techmely/utils
 * Copyright(c) 2021-2024 Techmely <techmely.creation@gmail.com>
 * MIT Licensed
 */

"use strict";
var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __getOwnPropNames = Object.getOwnPropertyNames;
var __hasOwnProp = Object.prototype.hasOwnProperty;
var __export = (target, all) => {
  for (var name in all)
    __defProp(target, name, { get: all[name], enumerable: true });
};
var __copyProps = (to, from, except, desc) => {
  if (from && typeof from === "object" || typeof from === "function") {
    for (let key of __getOwnPropNames(from))
      if (!__hasOwnProp.call(to, key) && key !== except)
        __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
  }
  return to;
};
var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);

// src/mergeStreams.ts
var mergeStreams_exports = {};
__export(mergeStreams_exports, {
  mergeStreams: () => mergeStreams
});
module.exports = __toCommonJS(mergeStreams_exports);
var import_node_stream = require("stream");

// src/invariant.ts
var prefix = "Invariant failed";
function invariant(condition, message) {
  if (condition) {
    return;
  }
  if (typeof message === "string" || typeof message === "function") {
    const provided = typeof message === "function" ? message() : message;
    const value = provided ? `${prefix}: ${provided}` : prefix;
    throw new Error(value);
  }
  if (message)
    throw message;
  throw new Error(prefix);
}

// src/isArray.ts
function isArray(val) {
  return val && Array.isArray(val);
}

// src/mergeStreams.ts
function mergeStreams(streams) {
  invariant(isArray(streams), "Expect input an array streams");
  const passThroughStream = new import_node_stream.PassThrough({ objectMode: true });
  if (streams.length === 0) {
    passThroughStream.end();
    return passThroughStream;
  }
  let streamsCount = streams.length;
  for (const stream of streams) {
    invariant(!(typeof stream?.pipe === "function"), "Expect a stream, got ");
    stream.pipe(passThroughStream, { end: false });
    stream.on("end", () => {
      streamsCount--;
      if (streamsCount === 0) {
        passThroughStream.end();
      }
    });
    stream.on("error", (error) => {
      passThroughStream.emit("error", error);
    });
  }
  return passThroughStream;
}
// Annotate the CommonJS export names for ESM import in node:
0 && (module.exports = {
  mergeStreams
});