Uses Of Underscore.js In Angular js

I going to explain how we can use Underscore js in Angularjs, It is very useful when we want to filter, search etc on an Array Dataset.

Introduction:-

Underscore is a JavaScript library that offers a no. of helpful programming while not extending any integrated web app. It’s the answer to the question: “If I take a seat down in front of a clean HTML page, and want to start being productive immediately, what do I want?”  … and the tie to go together with jQuery's suit and determination's suspenders.

Underscore presents over a hundred of options that assist every your favoured ordinary helpful functions like map, filter out, invoke — moreover as a lot of specialised functionality: feature binding, javascript templating, creating brief indexes, deep equality checking out, and so forth.

Download the file from http://underscorejs.org/ and add to your project module, In angular controller add this code.

angular.module('underscore', []).factory('_', function() {

    return window._; // assumes underscore has already been loaded on the page

});

In controller:

loginApp.controller('newCalendarCtrl',['$scope','_',function($scope,_) {}]);

Examples:-

ForEach: Iterates over a list.

_.each([1, 2, 3], warning);

output: warning each no. in turn. 

Map: Create a new Array of the objects by mapping each object in a list.

_.map([1, 2, 3], function(number){ return number * 3; });

output:[3,6,9]

Reduce: It can be used for the sum of all no. in an array.

var total = _.reduce([1, 2, 3], function(initial, num){ return initial + num; }, 0);

output: 6

Find: find a value in a list on matching condition.

var evenNumber = _.find([1, 2, 3, 4, 5, 6], function(value){ return value % 2 == 0; });

output:2

filter: It uses for filtering in a list on matching condition.

var evenvalue = _.filter([11, 12, 32, 41, 50, 64], function(number){ return number % 2 == 0; });

output:[2,4,6]

where: It is an advanced version of _.filter it can be use matching key and value pair.

_.where(listOfPlays, {writer: "shakespeare", year: 2018});

output:[{name:"leadership",writer:"shakespeare",year:2018},{name:"romeo-juliet",writer:"shakespeare",year:2018}]