JavaScript Array filter()

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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 »

Description

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
Array	An array of elements that pass the test. An empty array if no elements pass the test.

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>

Array Iteration Methods