js deepFreeze

deepFreeze.js

/**
 * Will deep freeze any object recursively. And it supports circular references.
 */
function deepCloneAndFreeze(arg) {
  const circularFrozenRefMap = new WeakMap();
  function deepCloneAndNativeFreeze(arg) {
    const clone = Array.isArray(arg) ? [] : {};
    circularFrozenRefMap.set(arg, clone);

    const isObject = input => typeof input === 'object';
    const isCircularDependency = object => circularFrozenRefMap.has(object);
    const deepFreezeWhenObject = key => {
      const value = arg[key];
      if (isObject(value)) {
        if (isCircularDependency(value)) {
          clone[key] = circularFrozenRefMap.get(value);
        } else {
          clone[key] = deepCloneAndNativeFreeze(value);
        }
      } else {
        clone[key] = value;
      }
    };

    Object.getOwnPropertySymbols(arg).forEach(deepFreezeWhenObject);
    Object.getOwnPropertyNames(arg).forEach(deepFreezeWhenObject);

    return Object.freeze(clone);
  }
  return deepCloneAndNativeFreeze(arg);
}