Underscore.JS - functions method

Syntax

_.findKey(object, predicate, [context])

findKey method returns the keys of object if predicate is true on keys. See the below example −

Example

var _ = require('underscore');

var users = [{'id': 1, 'name': 'Sam', 'last': 'Brown'},
             {'id': 2, 'name': 'Joe', 'last': 'Black'},
             {'id': 3, 'name': 'Julie', 'last': 'Jordon'},
             {'id': 4, 'name': 'Tim', 'last': 'Jane'}];

// Get index of first user whose id is even
var result = _.findKey(users, function(user){ return user.id % 2 == 0});
console.log(result);

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

Command

\>node tester.js

Output

1