-
Notifications
You must be signed in to change notification settings - Fork 0
/
script.js
228 lines (192 loc) · 6.36 KB
/
script.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
////////////////////////////////////////////////////////////////////////////////////////////
// Constructor function and the new Operator
////////////////////////////////////////////////////////////////////////////////////////////
// constructor function
const Person = function (firstName, birthYear) {
this.firstName = firstName;
this.birthYear = birthYear;
// Problem 1: not a good practice to use this. copy will be created for each instance
// this.age = function () {
// return new Date().getFullYear() - this.birthYear;
// }
}
/*
Steps (new operator) v:
1. new {} is created
2. function is called, this = {}
3. {} linked to prototype (__proto__)
4. function automatically return {}
*/
// create new instance of Person
const john = new Person('John', 1990)
console.log(john)
console.log(john instanceof Person)
// to solve problem 1 - Prototype creates only one copy of age function
Person.prototype.age = function () {
return new Date().getFullYear() - this.birthYear;
}
console.log(john.age())
console.log(john.__proto__) // prototype of john, Step 3 connect john's prototype to Person.prototype
console.log(john.__proto__ === Person.prototype) // true
// prototype of linked objects
console.log(Person.prototype.isPrototypeOf(john)) // true
console.log(Person.prototype.isPrototypeOf(Person)) // false
// has own property
Person.prototype.species = 'Human'
console.log(john.species)
console.log(john.hasOwnProperty('species')) // false
console.log(john.__proto__) // john's prototype
console.log(john.__proto__.__proto__) // object's prototype
console.log(john.__proto__.__proto__.__proto__) // null
console.log(Person.prototype.constructor) // Person
// Arrays
const arr = [3, 6, 4, 5, 6, 7, 6] // [] === new Array()
console.log(arr.__proto__) // Array.prototype
console.log(arr.__proto__ == Array.prototype) // Object.prototype
Array.prototype.unique = function () {
return [...new Set(this)]
}
console.log(arr.unique())
// basic challange
const car = function (make, speed) {
this.make = make;
this.speed = speed;
}
car.prototype.accelerate = function () {
this.speed += 10;
console.log(`${this.make} is accelerating to ${this.speed}`)
}
car.prototype.decelerate = function () {
this.speed -= 5;
console.log(`${this.make} is decelerating to ${this.speed}`)
}
const bmw = new car('BMW', 100)
bmw.accelerate()
bmw.decelerate()
////////////////////////////////////////////////////////////////////////////////////////////
// ES6 classes
////////////////////////////////////////////////////////////////////////////////////////////
class PersonCl {
constructor(fullName, birthYear) {
this.fullName = fullName;
this.birthYear = birthYear;
}
calcAge() {
return new Date().getFullYear() - this.birthYear;
}
// getter
get age() {
return new Date().getFullYear() - this.birthYear;
}
set fullName(name) {
console.log(name)
if (name.includes(' ')) {
this._fullName = name;
}
}
get fullName() {
return this._fullName;
}
// static method
static hey() {
console.log('Hello')
console.log(this)
}
}
const jessica = new PersonCl('jessica davis', 1996)
console.log(jessica)
console.log(jessica.calcAge())
console.log(jessica.age)
console.log(jessica.__proto__ === PersonCl.prototype) // true
PersonCl.prototype.greet = function () {
return `Hello ${this.fullName}`
}
console.log(jessica.greet())
const walter = new PersonCl('Walter', 1980)
console.log(walter)
PersonCl.hey()
////////////////////////////////////////////////////////////////////////////////////////////
// Object.create
////////////////////////////////////////////////////////////////////////////////////////////
// only difference is constructor function is not required
const PersonProto = {
calcAge: function () {
return new Date().getFullYear() - this.birthYear;
}
}
const steven = Object.create(PersonProto)
console.log(steven)
steven.name = 'Steven'
steven.birthYear = 1990
////////////////////////////////////////////////////////////////////////////////////////////
// Inheritance
////////////////////////////////////////////////////////////////////////////////////////////
const PersonInherit = function (firstName, birthYear) {
this.firstName = firstName;
this.birthYear = birthYear;
}
PersonInherit.prototype.calcAge = function () {
return new Date().getFullYear() - this.birthYear;
}
const StudentInherit = function (firstName, birthYear, major) {
PersonInherit.call(this, firstName, birthYear)
this.major = major;
}
// Linking prototypes
StudentInherit.prototype = Object.create(PersonInherit.prototype)
StudentInherit.prototype.introduce = function () {
return `Hello, my name is ${this.firstName} and I am ${this.age} years old.`
}
const mike = new StudentInherit('Mike', 1990, 'Computer Science')
console.log(mike.introduce())
console.log(mike.calcAge())
////////////////////////////////////////////////////////////////////////////////////////////
// Inheritance Between "Classes": ES6 Classes
////////////////////////////////////////////////////////////////////////////////////////////
class PersonClES6 {
constructor(fullName, birthYear) {
this.fullName = fullName;
this.birthYear = birthYear;
}
// Instance methods
calcAge() {
console.log(2037 - this.birthYear);
}
greet() {
console.log(`Hey ${this.fullName}`);
}
get age() {
return 2037 - this.birthYear;
}
set fullName(name) {
if (name.includes(' ')) this._fullName = name;
else alert(`${name} is not a full name!`);
}
get fullName() {
return this._fullName;
}
// Static method
static hey() {
console.log('Hey there 👋');
}
}
class StudentClES6 extends PersonClES6 {
constructor(fullName, birthYear, course) {
// Always needs to happen first!
super(fullName, birthYear);
this.course = course;
}
introduce() {
console.log(`My name is ${this.fullName} and I study ${this.course}`);
}
calcAge() {
console.log(
`I'm ${2037 - this.birthYear
} years old, but as a student I feel more like ${2037 - this.birthYear + 10
}`
);
}
}
const martha = new StudentClES6('Martha Jones', 2012, 'Computer Science');
martha.introduce();
martha.calcAge();