Underscore.JS - findIndex method

Syntax

_.findIndex(array, predicate, [context])

findIndex method return the first index of element in array using predicate function applied on each element.

Example

var _ = require('underscore');

var list = [1, 2, 4, 5, 6]
//Example: get index of first even number
result = _.findIndex(list, function(x){ return x % 2 == 0} );
console.log(result)

list = [{name: 'Joe', age: 40}, {name: 'Rob', age: 60}];
//Example: get index of employee of age: 60
result = _.findIndex(list, function(x){ return x.age == 60} );
console.log(result)

Save the above program in tester.js. Run the following command to execute this program.

Command

\>node tester.js

Output

1
1