for, for..of, and for..in loops in JavaScript
By: Tanya in Javascript Tutorials on 2023-04-25
In JavaScript, there are several ways to loop through arrays and objects. Here's an overview of the for
, for..of
, and for..in
loops:
for
loop:
The basic for
loop is used to iterate over a range of numbers or indices in an array.
Syntax:
for (initialization; condition; increment) { // code to be executed }
Example:
for (let i = 0; i < 10; i++) { console.log(i); }
for..of
loop:
The for..of
loop is used to iterate over the values of an iterable object, such as an array or a string.
Syntax:
for (variable of iterable) { // code to be executed }
Example:
const arr = ['apple', 'banana', 'orange']; for (const fruit of arr) { console.log(fruit); }
Output:
apple banana orange
for..in
loop:
The for..in
loop is used to iterate over the properties of an object, such as the keys in a key-value pair.
Syntax:
for (variable in object) { // code to be executed }
Example:
const person = { name: 'John', age: 30, gender: 'male' }; for (const prop in person) { console.log(`${prop}: ${person[prop]}`); }
Note that this line console.log(`${prop}: ${person[prop]}`);
is using a Template Literal
Output:
name: John age: 30 gender: male
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