$(document).ready(function() { module("Function functions (bind, bindAll, and so on...)"); test("functions: bind", function() { var context = {name : 'moe'}; var func = function(arg) { return "name: " + (this.name || arg); }; var bound = _.bind(func, context); equals(bound(), 'name: moe', 'can bind a function to a context'); bound = _(func).bind(context); equals(bound(), 'name: moe', 'can do OO-style binding'); bound = _.bind(func, null, 'curly'); equals(bound(), 'name: curly', 'can bind without specifying a context'); func = function(salutation, name) { return salutation + ': ' + name; }; func = _.bind(func, this, 'hello'); equals(func('moe'), 'hello: moe', 'the function was partially applied in advance'); var func = _.bind(func, this, 'curly'); equals(func(), 'hello: curly', 'the function was completely applied in advance'); }); test("functions: bindAll", function() { var curly = {name : 'curly'}, moe = { name : 'moe', getName : function() { return 'name: ' + this.name; }, sayHi : function() { return 'hi: ' + this.name; } }; curly.getName = moe.getName; _.bindAll(moe, 'getName', 'sayHi'); curly.sayHi = moe.sayHi; equals(curly.getName(), 'name: curly', 'unbound function is bound to current object'); equals(curly.sayHi(), 'hi: moe', 'bound function is still bound to original object'); curly = {name : 'curly'}; moe = { name : 'moe', getName : function() { return 'name: ' + this.name; }, sayHi : function() { return 'hi: ' + this.name; } }; _.bindAll(moe); curly.sayHi = moe.sayHi; equals(curly.sayHi(), 'hi: moe', 'calling bindAll with no arguments binds all functions to the object'); }); test("functions: memoize", function() { var fib = function(n) { return n < 2 ? n : fib(n - 1) + fib(n - 2); }; var fastFib = _.memoize(fib); equals(fib(10), 55, 'a memoized version of fibonacci produces identical results'); equals(fastFib(10), 55, 'a memoized version of fibonacci produces identical results'); }); asyncTest("functions: delay", function() { var delayed = false; _.delay(function(){ delayed = true; }, 100); _.delay(function(){ ok(!delayed, "didn't delay the function quite yet"); }, 50); _.delay(function(){ ok(delayed, 'delayed the function'); start(); }, 150); }); asyncTest("functions: defer", function() { var deferred = false; _.defer(function(bool){ deferred = bool; }, true); _.delay(function(){ ok(deferred, "deferred the function"); start(); }, 50); }); test("functions: wrap", function() { var greet = function(name){ return "hi: " + name; }; var backwards = _.wrap(greet, function(func, name){ return func(name) + ' ' + name.split('').reverse().join(''); }); equals(backwards('moe'), 'hi: moe eom', 'wrapped the saluation function'); }); test("functions: compose", function() { var greet = function(name){ return "hi: " + name; }; var exclaim = function(sentence){ return sentence + '!'; }; var composed = _.compose(exclaim, greet); equals(composed('moe'), 'hi: moe!', 'can compose a function that takes another'); composed = _.compose(greet, exclaim); equals(composed('moe'), 'hi: moe!', 'in this case, the functions are also commutative'); }); });