TrejGun

import { Writable } from "stream";


export const streamAsPromise = (readable: Readable): Promise<Buffer> => {
  const result: Array<Buffer> = [];
  const w = new Writable({
    write(chunk, encoding, callback) {
      result.push(chunk);
      callback();
    },

TrejGun

import { Readable } from "stream";

export const getReadableStream = (buffer: Buffer): Readable => {
  const stream = new Readable();
  stream.push(buffer);
  stream.push(null);
  return stream;
};

TrejGun

export const mapSeries = <T>(tasks: Array<() => Promise<T>>): Promise<Array<T>> => {
  return tasks.reduce((promiseChain, currentTask) => {
    return promiseChain.then(chainResults => currentTask().then(currentResult => [...chainResults, currentResult]));
  }, Promise.resolve([] as Array<T>));
};

TrejGun

export const fisherYates = <T>(array: Array<T>): Array<T> => {
  for (let i = array.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [array[i], array[j]] = [array[j], array[i]];
  }
  return array;
};

TrejGun

export const chunkBy = <T>(array: Array<T>, size = 1): Array<Array<T>> => {
  const arrayChunks: Array<Array<T>> = [];
  for (let pointer = 0; pointer < array.length; pointer += size) {
    arrayChunks.push(array.slice(pointer, pointer + size));
  }
  return arrayChunks;
};