JavaScript Array filter() Method
The filter() method creates a new array filled with elements that pass a test provided by a function. It’s a powerful tool for selectively extracting data from arrays based on specified criteria. Notably, it ignores empty elements, enhancing its efficiency and reliability in data filtering operations.
Syntax:
array.filter(callback(element, index, arr), thisValue)
Parameters:
This method accepts five parameters as mentioned above and described below:
| Parameter | Description |
|---|---|
| callback | The function is to be called for each element of the array. |
| element | The value of the element currently being processed. |
| index | (Optional) The index of the current element in the array, starting from 0. |
| arr | (Optional) The complete array on which Array.every is called. |
| thisValue | (Optional) The context to be passed as this to be used while executing the callback function. If not provided, undefined is used as the default context. |
Return value:
It returns an array of elements that pass the test and an empty array if no elements pass the test.
Example 1: In this example, the method filter() creates a new array consisting of only those elements that satisfy the condition checked by canVote() function.
// JavaScript to illustrate findIndex() method
function canVote(age) {
return age >= 18;
}
function func() {
let filtered = [24, 33, 16, 40].filter(canVote);
console.log(filtered);
}
func();
Output:
[24,33,40]
Example 2: In this example, the method filter() creates a new array consisting of only those elements that satisfy the condition checked by isPositive() function.
function isPositive(value) {
return value > 0;
}
let filtered = [112, 52, 0, -1, 944].filter(isPositive);
console.log(filtered);
Output:
[112,52,944]
Example 3: In this example, the method filter() creates a new array consisting of only those elements that satisfy the condition checked by isEven() function.
function isEven(value) {
return value % 2 == 0;
}
let filtered = [11, 98, 31, 23, 944].filter(isEven);
console.log(filtered);
Output:
[98,944]
We have a complete list of Javascript Array methods, to check those please go through this Javascript Array Complete reference article.
Supported Browsers:
The browsers supported by the JavaScript Array filter() method are listed below:
We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.