Underscore.JS - where method

Syntax

_.where(list, properties)

where method iterates over a given list of element, calls the predicate on each element. It returns the all matched key-value pairs in properties.

Looks through each value in the list, returning an array of all the values that matches the key-value pairs listed in properties.

Example

var _ = require('underscore');

var list = [{"title": "Learn Java", "Author": "Sam", "Cost": 100},
   {"title": "Learn Scala", "Author": "Joe", "Cost": 200},
   {"title": "Learn C", "Author": "Sam", "Cost": 200} ]
   
//Example 1. find books whose author is Sam
var result = _.where(list, { "Author": "Sam" });
console.log(result);

//Example 2. find books whose cost is 200
var result = _.where(list, { "Cost": 200 });
console.log(result);

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

Command

\>node tester.js

Output

[
  { title: 'Learn Java', Author: 'Sam', Cost: 100 },
  { title: 'Learn C', Author: 'Sam', Cost: 200 }
]
[
  { title: 'Learn Scala', Author: 'Joe', Cost: 200 },
  { title: 'Learn C', Author: 'Sam', Cost: 200 }
]