JavaScript Array filter()

Definition and Usage

filter() The method creates an array filled with all array elements that pass the test (as a function provided).

Note:filter() This function will not be executed for array elements without values.

Note:filter() It will not change the original array.

Example

Example 1

Return an array consisting of all values 18 years of age or older in the ages array:

var ages = [32, 33, 16, 40];
function checkAdult(age) {
  return age >= 18;
}
function myFunction() {
  document.getElementById("demo").innerHTML = ages.filter(checkAdult);
}

Try it yourself

Example 2

Return an array consisting of all values greater than or equal to a specific number in the ages array:

<p>Minimum age: <input type="number" id="ageToCheck" value="18"></p>
<button onclick="myFunction()">Try it</button>
<p>All ages above minimum: <span id="demo"></span></p>
<script>
var ages = [32, 33, 12, 40];
function checkAdult(age) {
  return age >= document.getElementById("ageToCheck").value;
}
function myFunction() {
  document.getElementById("demo").innerHTML = ages.filter(checkAdult);
}
</script>

Try it yourself

Syntax

array.filter(function(currentValue, index, arr) thisValue)

Parameter value

Parameter Description
function(currentValue, index, arr) Required. A function to be run for each element in the array.

Function parameters:

Parameter Description
currentValue Required. The value of the current element.
index Optional. The array index of the current element.
arr Optional. The array object to which the current element belongs.
thisValue

Optional. The value to be passed to the function to be used as its 'this' value.

If this parameter is empty, the value 'undefined' will be passed as its 'this' value.

Technical details

Return value: An array containing all array elements that pass the test. If no elements pass the test, an empty array is returned.
JavaScript version: ECMAScript 5

Browser support

All browsers fully support filter() Method:

Chrome IE Edge Firefox Safari Opera
Chrome IE Edge Firefox Safari Opera
Support 9.0 Support Support Support Support

Related Pages

Tutorial:JavaScript Array

Tutorial:JavaScript Array Const

Tutorial:JavaScript Array Methods

Tutorial:JavaScript Sorting Arrays

Tutorial:JavaScript Array Iteration