text: // @flow
  
  // Deep freeze an object by using a Proxy.
  // This is better than Object.freeze() as we can create coherent error messages
  // and easily only deliver frozen subobjects when they are accessed. We can
  // even add custom logic, like warning if you access a property that doesn't exist.
  /* eslint-disable no-console */
  export default function deepFreeze<T>(inputObj: T, options: {get: boolean, set: boolean} = {get: true, set: true}): $ReadOnly<{|...T|}> {
    // Our handler that rejects any change to the object and any nested objects inside it
    const deepFreezer = {};
    if (options.get) {
      deepFreezer.get = function get<T: Object>(obj: T, prop: $Keys<T>, _receiver: Proxy<T>) {
        // Clone w/o Proxy
        if (prop === 'toJSON') return () => obj;
        // If dealing with nested object, nest the proxy untill it reaches the direct property of it's parent proxy
        if (typeof obj[prop] === 'object' && obj[prop] !== null) {
          return new Proxy(obj[prop], deepFreezer);
        }
        // If prop is directly accessible, just do the default operation
        else {
          if (!(prop in obj) && prop !== 'length' && prop !== '__esModule' && typeof prop !== 'symbol') {
            throw new Error(`Can not get unknown prop "${String(prop)}" on frozen object.`);
          }
          return obj[prop];
        }
      };
    }
    if (options.set) {
      deepFreezer.set = function set<T>(obj: T, prop: string, _val: any, _rec: Proxy<T>): boolean {
        throw new Error(`Can not set unknown prop "${prop}" on frozen object.`);
      };
    }
    // $FlowIgnore for all useful purposes the output type is T here
    return new Proxy(inputObj, deepFreezer);
  }