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JavaScript Array filter()

Example 1

Return an array of all values in ages[] that are 18 or over:

const ages = [32, 33, 16, 40];
const result = ages.filter(checkAdult);

function checkAdult(age) {
  return age >= 18;
}
Try it Yourself »

Definition and Usage

The filter() method creates a new array filled with elements that pass a test provided by a function.

The filter() method does not execute the function for empty elements.

The filter() method does not change the original array.


Syntax

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

Parameters

Parameter Description
function() Required.
A function to run for each array element.
currentValue Required.
The value of the current element.
index Optional.
The index of the current element.
arr Optional.
The array of the current element.
thisValue Optional. Default undefined
A value passed to the function as its this value.

Return Value

Type Description
An array Containing the elements that pass the test.
If no elements pass the test it returns an empty array.

Example 2

Return the values in ages[] that are over a specific number:

<p><input type="number" id="ageToCheck" value="30"></p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
const ages = [32, 33, 12, 40];

function checkAge(age) {
  return age > document.getElementById("ageToCheck").value;
}

function myFunction() {
  document.getElementById("demo").innerHTML = ages.filter(checkAge);
}
</script>
Try it Yourself »


Browser Support

filter() is an ECMAScript5 (ES5) feature.

ES5 (JavaScript 2009) fully supported in all browsers:

Chrome Edge Firefox Safari Opera IE
Yes Yes Yes Yes Yes 9-11