JavaScript原型繼承
function A() {
this.a = 'A'
}
A.prototype.showA = function () {
console.log(this.a)
};
function B() {
A.call(this);
this.b = 'B'
}
B.prototype = Object.create(A.prototype);
B.prototype.constructor = B; // 把B原型的構(gòu)造函數(shù)修復為B
B.prototype.showB = function () {
console.log(this.b)
};
b = new B();
b.showA();
b.showB();
console.log('b instanceof B: ', b instanceof B);
console.log('b instanceof A: ', b instanceof A);
打印結(jié)果：
A
B
b instanceof B: true
b instanceof A: true
封裝可復用繼承函數(shù)：
function inherit(parent, child) {
child.prototype = Object.create(parent.prototype);
child.prototype.constructor = child;
}
實現(xiàn)繼承：
function A(a) {
this.a = a
}
A.prototype.showA = function () {
console.log(this.a)
};
function B(a, b) {
A.call(this, a);
this.b = b
}
inherit(A, B); // 繼承
B.prototype.showB = function () {
console.log(this.b)
};
b = new B('aaa', 'bbb');
console.log(b.a);
console.log(b.b);
b.showA();
b.showB();
console.log('b instanceof B: ', b instanceof B);
console.log('b instanceof A: ', b instanceof A);
打印結(jié)果：
aaa
bbb
aaa
bbb
b instanceof B: true
b instanceof A: true
學習參考：
https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Inheritance_and_the_prototype_chain
https://www.liaoxuefeng.com/wiki/1022910821149312/1023021997355072
