Part 3

[1, 2, 3] + [4, 5, 6]

[1, 2, 3] + [4, 5, 6] // -> '1,2,34,5,6'

console.log(1 <2 <3)
console.log(3> 2> 1)

console.log(1 <2 <3) // -> true
console.log(3> 2> 1) // -> false

var a = 10;
function Foo() {
if (true) {
let a = 5;
}
alert(a);
}
Foo();

var a = 10;
function Foo() {
if (true) {
let a = 5;
}
alert(a); //10
}
Foo();

Как очистить массив?
let arr = [1,2,3];

1. arr = [];
2. arr.length = 0;
3. arr.splice(0, arr.length);
4. while(arr.length) {
arr.pop();
}

const test1 = 1;
if(true){
const test2 = 2;
}
console.log(test1);
console.log(test2);