key-mirror.ts 🪞

Published by Alicia's Notes 🚀, View original

A quick function to construct an enumeration which has keys the same as their value

This used to be part of React, but since it's now been removed (See commit: #56f5115), and some older packages throw an error without it, I've updated it, and uploading in case anyone else needs it while working with older React packages. A copy of React's original, JavaScript version can be found here.

 * (C) Alicia Sykes <>
 * Licensed under MIT X11:
 * Constructs an enumeration with keys equal to their value.
 * @param {object} obj
 * @return {object}
export function keyMirror(originObj: object) {
  if (typeof originObj !== 'object')
    throw new Error('keMirror(...): Argument must be an object');
  const obj: any = {};
  for (const key in originObj) {
    if (originObj.hasOwnProperty(key)) obj[key] = key;
  return obj