JavaScript Array every() Method

The Array.every() method is a built-in JavaScript function used to test whether all elements in an array pass a specified condition implemented by a callback function. It returns a boolean value: true if all elements satisfy the condition, and false otherwise.

Syntax

arr.every(callback(element, index, array), thisArg);

Parameters

Parameter	Description
callback	(Required) A function that tests each element of the array.
element	(Required) The current element being processed in the array.
index	(Optional) The index of the current element being processed in the array.
array	(Optional) The array every() was called on.
thisArg	(Optional) A value to use as this when executing the callback function. Defaults to undefined.

Return Value

The every() method returns –

• true if the callback function returns true for every array element.
• false if the callback function returns false for at least one array element.

Example 1: Checks all elements in the array are even numbers.

let arr = [2, 4, 6, 8];

let result = arr.every(num => num % 2 === 0);
console.log(result); // Output: true

Example 2: The every() method verifies that every string in the array has more than 2 characters.

let arr = ['apple', 'banana', 'cherry'];

let result = arr.every(word => word.length > 2);
console.log(result); // Output: true

Example 3: Using with Objects – checks whether all users are active.

let users = [
    { id: 1, name: 'John', isActive: true },
    { id: 2, name: 'Alice', isActive: true },
    { id: 3, name: 'Bob', isActive: false }
];

let allActive = users.every(user => user.isActive);
console.log(allActive); // Output: false

Example 4: Handling Empty Arrays – The every() always returns true because there are no elements to violate the condition.

let emptyArray = [];

let result = emptyArray.every(num => num > 0);
console.log(result); // Output: true

Example 6: The thisArg parameter binds the context object to the callback function.

let context = { minAge: 18 };

let ages = [20, 25, 30];

let allAdults = ages.every(function(age) {
  return age >= this.minAge;
}, context);

console.log(allAdults); // Output: true

Supported Browsers

Browser	Support
Chrome	1+
Firefox	1.5+
Safari	3+
Edge	12+
Opera	9.5+
Internet Explorer	9+