Hi everybody,

I have the following two functions:

function isEmpty(value) {
        return angular.isUndefined(value) || value === '' || value === null || value !== value;
    }

    function sort_by(field, reverse) {
        var key = function (x) { return x[field]; };
        reverse = [-1, 1][+!!reverse];

        return function (a, b) {
            return a = key(a), b = key(b), reverse * ((a > b) - (b > a));
        }
    }

I want to be able to use them from different controllers. The question is - where exactly should I put them to be able to call from my controllers?

I tried in the app.js here

(function () {
    'use strict';

    var app = angular.module('sysMgrApp', ['ui.router', 'ngSanitize', 'ngAnimate', 'toastr', 'ngCookies',
    'ui.bootstrap', 'ui.sortable', 'ngDragDrop', 'colorpicker.module', 'ui.ace',
    'resourceModule', 'ngFileUpload', 'ui.bootstrap.datetimepicker', 'ngMessages', 'ui.grid', 'spinnerService']);

    // here I tried to put these two functions

but this didn't work - my controller was unable to find them.

What is the most common practice of having a library of simple common functions?

Thanks in advance.