for...in array javascript code example

Example 1: javascript loop object

let obj = {
  key1: "value1",
  key2: "value2",
  key3: "value3"
}

Object.keys(obj).forEach(key => {
    console.log(key, obj[key]);
});
// key1 value1
// key2 value2
// key3 value3

// using for in - same output as above
for (let key in obj) {
  let value = obj[key];
  console.log(key, value);
}

Example 2: loop array javascript

var colors = ['red', 'green', 'blue'];
	
	colors.forEach((color, colorIndex) => {
     console.log(colorIndex + ". " + color); 
    });

Example 3: javascript for of

const array = ['hello', 'world', 'of', 'Corona'];

for (const item of array) {
  console.log(item);
}

Example 4: for in javascript

const object = {a: 1, b: 2, c: 3};

for (const property in object) {
  console.log(`${property}: ${object[property]}`);
}

// expected output:
// "a: 1"
// "b: 2"
// "c: 3"

Example 5: for in javascript

for (let i = start; i < end; i++) {

}

Example 6: how to use for of in javascript

const array1 = ['a', 'b', 'c'];

for (const element of array1) {
  console.log(element);
}