var a = [1,2,3];
var b = a.concat(6,7);
console.log(a); //[1,2,3]
console.log(b); //[1,2,3,6,7]

var a = [1,2,3]
var b = a.join('|');
console.log(a); //[1,2,3]
console.log(b); //"1|2|3"

var a = [1,2,3];
var b = a.pop();
console.log(a); //[1,2]
console.log(b); //3

var a = [1,2,3];
var b = a.push('4','5');
console.log(a); //[1,2,3,4,5]
console.log(b); //5

var a = [1,2,3,4,5];
var b = a.reverse();
console.log(a); //[5,4,3,2,1]
console.log(b); //[5,4,3,2,1]

var a = [1,2,3];
var b = a.shift();
console.log(a); //[2,3]
console.log(b); //1

var a = [1,2,3,4,5];
var b = a.slice(0,-1);
var c = a.slice(1,3);
var d = a.slice(1);
var e = a.slice(2,-2);
var f = a.slice(3,1);
console.log(a); //[1,2,3,4,5]
console.log(b); //[1,2,3,4]
console.log(c); //[2,3]
console.log(d); //[2,3,4,5]
console.log(e); //[3]
console.log(f); //[]

var a = [1,2,10,3];
var b = a.sort();
console.log(a); //[1,10,2,3]
console.log(b); //[1,10,2,3]
var num = function(x,y) {
  return x - y;
}
var c = a.sort(num);
console.log(a); //[1,2,3,10]
console.log(c); //[1,2,3,10]

var a = [1,2,3,4,5];
var b = a.splice(2,2,7,8);
console.log(a); //[1,2,7,8,5]
console.log(b); //[3,4]

var a = [1,2,3];
var b = a.unshift(-2,-1);
console.log(a); //[-2,-1,1,2,3]
console.log(b); //5

var a = [1,2,3,4,5];
var b = a.toString();
console.log(a); //[1,2,3,4,5]
console.log(b); //"1,2,3,4,5"