JavaScript Array shift() Method

The Array.shift() method is a built-in JavaScript function used to remove the first element from an array and return it. This method modifies the original array, reducing its length by one.

Syntax

arr.shift();

Parameters

The shift() method does not take any parameters.

Return Value

The shift() method returns:

• The removed first element of the array if the array is not empty.
• undefined if the array is empty.

Example 1: Removing the First Element

let arr = [10, 20, 30, 40, 50];

let item = arr.shift();
console.log(item); // Output: 10
console.log(arr);  // Output: [20, 30, 40, 50]

Example 2: Using shift() on an Empty Array

let arr = [];

let item = arr.shift();
console.log(item); // Output: undefined
console.log(arr);  // Output: []

When the array is empty, shift() method returns undefined without causing an error.

Example 3: Processing Elements in a Queue

let tasks = ['task1', 'task2', 'task3'];

while (tasks.length > 0) {
    let currentTask = tasks.shift();
    console.log(`Processing: ${currentTask}`);
}
// Output:
// Processing: task1
// Processing: task2
// Processing: task3

Supported Browsers

Browser	Support
Chrome	1+
Firefox	1+
Safari	1+
Edge	12+
Opera	4+
Internet Explorer	5.5+