The findIndex() method of JavaScript is used to return the index of the first element in an array, if the condition is passed.
The syntax is as follows −
array.findIndex(function(currentValue, index, arr), thisValue)
Let us now implement the findIndex() method in JavaScript −
Example
<!DOCTYPE html>
<html>
<body>
<h2>Rank</h2>
<button onclick="display()">Result</button>
<p id="demo"></p>
<p>Finding the index of the player with highest rank.</p>
<script>
var points = [100, 150, 200, 250, 300, 400];
function topRank(points) {
return points >= 400;
}
function display() {
document.getElementById("demo").innerHTML = "index = "+points.findIndex(topRank);
}
</script>
</body>
Output
Click “Result” to get the index −
Example
<!DOCTYPE html>
<html>
<body>
<h2>Rank</h2>
<button onclick="display()">Result</button>
<p id="demo"></p>
<p>Finding the index of the player with specific rank points.</p>
<script>
var points = [100, 150, 200, 250, 300, 400];
function topRank(points) {
return points == 200;
}
function display() {
document.getElementById("demo").innerHTML = "index = "+points.findIndex(topRank);
}
</script>
</body>
Output
Above, click the button “Result” −
