TypeScript | Array indexOf() Method

The Array.indexOf() is an inbuilt TypeScript function which is used to find the index of the first occurrence of the search element provided as the argument to the function. 
Syntax:

array.indexOf(searchElement[, fromIndex])

Parameter: This method accepts two parameter as mentioned above and described below: 

• searchElement : This parameter is the Element to locate in the array.
• fromIndex : This parameter is the index at which to begin the search.

Return Value: This method returns the index of the found element. 
Below examples illustrate the Array indexOf() method in TypeScript.

Example 1:

JavaScript

<script>
    // Driver code
    var arr = [ 11, 89, 23, 7, 98 ];

    // use of indexOf() method
    var val = arr.indexOf(7)

    // printing element
    console.log(val);
</script>

Output:

3

Example 2:

JavaScript

<script>
    // Driver code
    var arr = [ 'a','b','c','a','e' ];

    // use of indexOf() method
    var val = arr.indexOf('a',4)

    // printing element
    console.log(val);
</script>

Output:

-1