@techmely/utils/mergeStreams.global.js

Collection of helpful JavaScript / TypeScript utils

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

"use strict";
(() => {
  var __require = /* @__PURE__ */ ((x) => typeof require !== "undefined" ? require : typeof Proxy !== "undefined" ? new Proxy(x, {
    get: (a, b) => (typeof require !== "undefined" ? require : a)[b]
  }) : x)(function(x) {
    if (typeof require !== "undefined")
      return require.apply(this, arguments);
    throw Error('Dynamic require of "' + x + '" is not supported');
  });

  // src/mergeStreams.ts
  var import_node_stream = __require("node: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;
  }
})();