The _.pickWhen() method returns a copy of the object containing those properties for which the given predicate function returns true. The predicate function is invoked with each property value.
Syntax:
_.pickWhen( Object_name, predicate_func );
Parameters:
- Object_name: Object from which the key/value pair is to be picked.
- predicate_func: Given function which contains the conditions for properties is to be picked
Return Value: This method returns a copy of the object after containing properties.
Note: This will not work in normal JavaScript because it requires the underscore.js contrib library to be installed.
Underscore.js contrib library can be installed using npm install underscore-contrib –save.
Example 1:
Javascript
// Defining underscore contrib variable var _ = require( 'underscore-contrib' ); var obj = { 1: "Gfg1" , 2: "Gfg2" , 3: "Gfg3" }; var val = _.pickWhen(obj, function (id) { return id == "Gfg1" }); console.log(val); |
Output:
{ '1': 'Gfg1' }
Example 2: If no property is found in the object, this method picks nothing.
Javascript
// Defining underscore contrib variable var _ = require( 'underscore-contrib' ); var obj = { 1: "Gfg1" , 2: "Gfg2" , 3: "Gfg3" }; var val = _.pickWhen(obj, function (id) { return id == "Gfg4" }); console.log(val); |
Output:
{}