Javascript

clone_objects.js

let x = { greeting: 'Hello', infotext: 'lorem ispum sit dolor amet' }; 
let y = Object.assign({}, x); 
y.greeting = 'Worked'; 

console.log(x);
console.log(y);


/* 
So... what does this o?

Explanation:
- First we setup an object called, x with a key greeting and infotext.
- We create a new Object and we clone it from the previous one.
- We can now change the key value easily from the cloned object.

Demo:
https://es6console.com/jvmb5r70/
*/

let_it_go.js

let c = {greeting: "hello" }
let d, q

d = c
q = d

c.greeting = "Yow";
console.log(d.greeting);
console.log(q.greeting);


/* 
So... why does this work?

Explanation:
- Assignement doesn't copy, you still only have one object, just two names referring to it

Demo:
https://es6console.com/jvmasn0w/
*/

spread_operator.js

Javascript Spread operator ...

...  = SPREAD operator

It's basically the deconstructor for an array
const a, b, c = ...['foo', 'bar', 'baz'];
puts 'foo' in a, 'bar' in b etc,

Example:
this.errors.push(...errors) === this.errors.push(errors[0], errors[1], etc.)

Extra information:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

It's also how you can append array items to another array

const a = ['foo'];   const b = ['bar', ...a];   
console.log(b); // ['bar', 'foo

const a = ['foo'];   const b = ['bar', ...a];   
console.log(b); // ['bar', 'foo']

Works only in babel/webpack, no IE support.