iterate through an array in js code example

Example 1: javascript loop through array

var data = [1, 2, 3, 4, 5, 6];

// traditional for loop
for(let i=0; i<=data.length; i++) {
  console.log(data[i])  // 1 2 3 4 5 6
}

// using for...of
for(let i of data) {
	console.log(i) // 1 2 3 4 5 6
}

// using for...in
for(let i in data) {
  	console.log(i) // Prints indices for array elements
	console.log(data[i]) // 1 2 3 4 5 6
}

// using forEach
data.forEach((i) => {
  console.log(i) // 1 2 3 4 5 6
})
// NOTE ->  forEach method is about 95% slower than the traditional for loop

// using map
data.map((i) => {
  console.log(i) // 1 2 3 4 5 6
})

Example 2: loop through javascript array

let colors = ['red', 'green', 'blue'];
for (const color of colors){
    console.log(color);
}

Example 3: how to loop through array of numbers in javascript

let numbers = [1,2,3,4,5];
let numbersLength = numbers.length;
for ( let i = 0; i < numbersLength; i++) {
    console.log (numbers[i]);
}

Example 4: iterate through array js

let arbitraryArr = [1, 2, 3];
// below I choose let, but var and const can also be used 
for (let arbitraryElementName of arbitraryArr) {
  console.log(arbitraryElementName);
}