Nicky_Cookie

let eventSymbol = Symbol('resize event');
console.log(typeof eventSymbol);//symbol
console.log(eventSymbol.toString());//symbol(resize event)

let s = Symbol('event');
let s2 = Symbol('event');
console.log(s===s2);//false

let s = Symbol.for('event');
let s2 = Symbol.for('event');
console.log(s===s2);//true

let s = Symbol.for('event');
let description = Symbol.keyFor(s);
console.log(description);//event

let a = {
	x:1
}
let b = {
	y:2
}
Object.setPrototypeOf(a,b);
console.log(a.y);//2

let a = {
	x:1
}
let b = {
	y:2
}
let target={};
Object.assign(target,a,b);
console.log(target);//{x:1,y:2}

let a = {
	x:1
}
let b = {
	x:2,
	y:3
}
let target={};
//Object.assign(target,a,b);
Object.assign(target,b,a);
console.log(target);//{x:2,y:3}

let ids=[9000,9001,9002];
let iter =ids[Symbol.iterator]();
iter.next();
iter.next();
iter.next();
console.log(iter.next());//{done:true, value:undefined}