1.
1 // call的3种作用
2 // 1.Using call to chain constructors for an object
3 function Product(name, price) {
4 this.name = name;
5 this.price = price;
6
7 if (price < 0) {
8 throw RangeError('Cannot create product ' +
9 this.name + ' with a negative price');
10 }
11 }
12
13 function Food(name, price) {
14 Product.call(this, name, price);
15 this.category = 'food';
16 }
17
18 function Toy(name, price) {
19 Product.call(this, name, price);
20 this.category = 'toy';
21 }
22
23 var cheese = new Food('feta', 5);
24 console.log(cheese);
25 var fun = new Toy('robot', 40);
26 console.log(fun);
27
28 // 2.Using call to invoke an anonymous function
29 var animals = [
30 { species: 'Lion', name: 'King' },
31 { species: 'Whale', name: 'Fail' }
32 ];
33
34 for (var i = 0; i < animals.length; i++) {
35 (function(i) {
36 this.print = function() {
37 console.log('#' + i + ' ' + this.species
38 + ': ' + this.name);
39 }
40 this.print();
41 }).call(animals[i], i);
42 }
43
44 // Using call to invoke a function and specifying the context for 'this'
45 // In below example, when we will call greet the value of this will be bind to object i.
46 function greet() {
47 var reply = [this.person, 'Is An Awesome', this.role].join(' ');
48 console.log(reply);
49 }
50
51 var i = {
52 person: 'Douglas Crockford', role: 'Javascript Developer'
53 };
54
55 greet.call(i); // Douglas Crockford Is An Awesome Javascript Developer
You can do anything you set your mind to, man!
Original: https://www.cnblogs.com/shamgod/p/5523504.html
Author: shamgod
Title: 面向对象的JavaScript-005-Function.prototype.call()的3种作用
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