A simple TypeScript function: Generates a random alpha-numeric ID with length of N

gen-unique.ts

/**
 * A function that generates a unique ID
 * Made up of N random characters, N numbers from end of timestamp, and shuffled using Math.random
 */
export default (totalLen: number = 5) => {
  // 1. Generate Random Characters
  const letters = (len: number, str: string = ''): string => {
    const newStr = () =>
      String.fromCharCode(65 + Math.floor(Math.random() * 26));
    return len <= 1 ? str : str + letters(len - 1, str + newStr());
  };
  // 2. Generate random numbers (based on time in milliseconds)                
  const numbers = (len: number) =>
    Date.now()
      .toString()
      .substr(-len);
  // 3. Shuffle order, with a multiplier of JavaScript's Math.random    
  return (letters(totalLen) + numbers(totalLen))
    .split('')
    .sort(() => 0.5 - Math.random())
    .join('');
};