Helper functions for the Safe Access Proxy article

HelperFunctionsForSafeProxyAccess.js

const isObject = obj => obj && typeof obj === 'object';
const hasKey = (obj, key) => key in obj;

const Undefined = new Proxy({}, {
    get: function(target, name){
        return Undefined;
    }
  });
const either = (val,fallback) => (val === Undefined? fallback : val);