JavaScript arrays provide a plethora of methods to manipulate and analyze their elements effectively. Among these methods, every()
stands out as a powerful tool for determining whether all elements in an array satisfy a given condition. In this article, we’ll delve into the every()
method, examining its syntax, functionality, and usage through comprehensive examples.
Syntax:
The syntax of the every()
method is straightforward:
array.every(callback[, thisArg])
Parameters:
callback
: A function to test each element of the array. It should returntrue
if the element passes the test, otherwisefalse
.thisArg
(optional): An optional object to be used asthis
when executing thecallback
function.
Return Value:
true
if the callback function returnstrue
for every element in the array; otherwise,false
.
Examples:
Let’s explore the every()
method with detailed examples:
Example 1:
let numbers = [1, 2, 3, 4, 5];
let allEven = numbers.every((num) => num % 2 === 0);
console.log(allEven); // Output: false
In this example, the every()
method is used to check if all elements in the numbers
array are even. Since not all elements are even, the result is false
.
Example 2:
let ages = [25, 30, 42, 50, 28];
let allAdults = ages.every((age) => age >= 18);
console.log(allAdults); // Output: true
Here, the every()
method is employed to determine if all elements in the ages
array represent adults (ages 18 and above). Since all elements meet this condition, the result is true
.
Example 3:
let temperatures = [-5, 10, 15, 20];
let allPositive = temperatures.every((temp) => temp >= 0);
console.log(allPositive); // Output: false
In this example, the every()
method is utilized to check if all elements in the temperatures
array are positive. Since there is a negative temperature, the result is false
.