How to get value from Object, with default value

Question

I constantly find myself passing config values to functions accessing them like this:

var arg1 = \'test1\';
if(isUndefined(config.args.arg1)){
  arg1 = config.ar         


        

Answer 1

With ES2018, you can now write options = { ...defaults, ...options }:

Spread syntax - JavaScript | MDN

Shallow-cloning (excluding prototype) or merging of objects is now possible using a shorter syntax than Object.assign().

const obj1 = { foo: 'bar', x: 42 };
const obj2 = { foo: 'baz', y: 13 };

const clonedObj = { ...obj1 };
// Object { foo: "bar", x: 42 }

const mergedObj = { ...obj1, ...obj2 };
// Object { foo: "baz", x: 42, y: 13 }