JavaScript Array findIndex() Method
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JavaScript Array findIndex() Method
❮ JavaScript Array Reference
Example
Get the index of the first element in the array that has a value of 18 or
more:
var ages = [3, 10, 18, 20];
function checkAdult(age)
return age >= 18;
function myFunction()
document.getElementById("demo").innerHTML = ages.findIndex(checkAdult);
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The result will be:
2Try it Yourself »
More "Try it Yourself" examples below.
Definition and Usage
The findIndex() method returns the index of the first element in an array that pass a
test (provided as a function).
The findIndex() method executes the function once for each element present in the
array:
- If it finds an array element where the function returns a true value, findIndex() returns the index of that array element (and does not check the remaining values)
- Otherwise it returns -1
Note: findIndex() does not execute the function for array
elements without values.
Note: findIndex() does not change the original array.
Browser Support
The numbers in the table specify the first browser version that fully supports the method.
| Method | |||||
|---|---|---|---|---|---|
| findIndex() | 45.0 | 12.0 | 25.0 | 7.1 | 32.0 |
Syntax
array.findIndex(function(currentValue, index, arr), thisValue)Parameter Values
| Parameter | Description | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| function(currentValue, index,arr) | Required. A function to be run for each element in the array. Function arguments:
| ||||||||
| thisValue | Optional. A 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 |
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Technical Details
| Return Value: | Returns the array element index if any of the elements in the array pass the test, otherwise it returns -1 |
|---|---|
| JavaScript Version: | ECMAScript 6 |
More Examples
Example
Get the index of the first element in the array that has a value above a
specific number:
<p>Minimum age: <input type="number" id="ageToCheck" value="18"></p>
<button onclick="myFunction()">Try it</button>
<p>Any ages above: <span id="demo"></span></p>
<script>
var ages = [4, 12, 16, 20];
function checkAdult(age)
return age >= document.getElementById("ageToCheck").value;
function myFunction()
document.getElementById("demo").innerHTML = ages.findIndex(checkAdult);
</script>
Try it Yourself »
❮ JavaScript Array Reference
