Description
The
findIndex()
method executes a function for each array element.
The
findIndex()
method returns the index (position) of the first element that passes a test.
The
findIndex()
method returns -1 if no match is found.
The
findIndex()
method does not execute the function for empty array elements.
The
findIndex()
method does not change the original array.
Syntax
array
.findIndex(
function(currentValue, index, arr), thisValue
)
Parameters
Parameter
Description
function()
Required.
A function to be run for each array element.
currentValue
Required.
The value of the current element.
index
Optional.
The index of the current element.
Optional.
The array of the current element.
thisValue
Optional. Default
undefined
.
A value passed to the function as its
this
value.
Return Value
Description
Number
The index of the first element that passes the test.
Otherwise -1.
Find the first element with a value above an input value:
<p><input type="number" id="toCheck" value="18"></p>
<button onclick="myFunction()">Test</button>
<p>Any values above: <span id="demo"></span></p>
<script>
const numbers = [4, 12, 16, 20];
function checkValue(x) {
return x > document.getElementById("toCheck").value;
}
function myFunction() {
document.getElementById("demo").innerHTML = numbers.findIndex(checkValue);
}
</script>
Try it Yourself »
Related Pages:
Array Tutorial
Array Const
Array Methods
Array Sort
Array Iterations
Browser Support
findIndex()
is an ECMAScript6 (ES6) feature.
ES6 (JavaScript 2015) is supported in all modern browsers:
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