for js

1var data = [1, 2, 3, 4, 5, 6];
2
3// traditional for loop
4for(let i=0; i<=data.length; i++) {
5  console.log(data[i])  // 1 2 3 4 5 6
6}
7
8// using for...of
9for(let i of data) {
10	console.log(i) // 1 2 3 4 5 6
11}
12
13// using for...in
14for(let i in data) {
15  	console.log(i) // Prints indices for array elements
16	console.log(data[i]) // 1 2 3 4 5 6
17}
18
19// using forEach
20data.forEach((i) => {
21  console.log(i) // 1 2 3 4 5 6
22})
23// NOTE ->  forEach method is about 95% slower than the traditional for loop
24
25// using map
26data.map((i) => {
27  console.log(i) // 1 2 3 4 5 6
28})

1var colors=["red","blue","green"];
2for (let i = 0; i < colors.length; i++) { 
3  console.log(colors[i]);
4}

1let obj = {
2  key1: "value1",
3  key2: "value2",
4  key3: "value3"
5}
6
7Object.keys(obj).forEach(key => {
8    console.log(key, obj[key]);
9});
10// key1 value1
11// key2 value2
12// key3 value3
13
14// using for in - same output as above
15for (let key in obj) {
16  let value = obj[key];
17  console.log(key, value);
18}

1for (var property in object) {
2  if (object.hasOwnProperty(property)) {
3    // Do things here
4  }
5}
6

1var i; //defines i
2for (i = 0; i < 5; i++) { //starts loop
3  console.log("The Number Is: " + i); //What ever you want
4}; //ends loop
5//Or:
6console.log("The Number Is: " + 0);
7console.log("The Number Is: " + 1);
8console.log("The Number Is: " + 2);
9console.log("The Number Is: " + 3);
10console.log("The Number Is: " + 4);
11//They do the same thing!
12//Hope I helped!

1let str = '';
2
3for (let i = 0; i < 9; i++) {
4  str = str + i;
5}
6
7console.log(str);
8// expected output: "012345678"
9