jsオブジェクトと関数の補完
2961 ワード
JS対象補充(把握)
クラスの宣言方法(了解)
クラス属性(把握)
JS関数補完
// 1) js , ,
var dic_obj = {
// : ( , )
'name':'Bob',
'eat':function () {
console.log(' ')
}
};
console.log(dic_obj.name,dic_obj['name']);
dic_obj.eat(); dic_obj['eat']();
// 2) js , ,
var obj = {
name: 'Tom',
eat: function () {
console.log(' ...')
}
};
console.log(obj.name,obj['name']);
obj.eat();obj['eat']();
// 3) , , (){}
var obj2 = {
name: 'Tom',
eat () {
console.log(' ...')
}
};
console.log(obj2.name,obj2['name']);
obj2.eat();obj2['eat']();
//4) , , { ,}
var height = 180;
var p = {
height,
name: 'Jerry'
};
console.log(p.name,p.height);
クラスの宣言方法(了解)
//js
//
class People {
constructor(name) {
this.name = name
}
eat () {
console.log(this.name + ' ')
}
}
let p1 = new People('Bob');
let p2 = new People('Tom');
console.log(p1.name,p2.name);
p1.eat();
// ( ): this , ,
function Teacher(name) {
this.name = name;
this.eat = function () {
console.log(this.name + ' ')
}
}
let t1 = new Teacher('Owen');
t1.eat();
クラス属性(把握)
// : ,
function Fn() {}
let f1 = new Fn();
let f2 = new Fn();
//
Fn.prototype.num = 100;
console.log(f1.num);
console.log(f2.num);
//
Vue.prototype.num = 1000;
let v1 = new Vue();
let v2 = new Vue();
console.log(v1.num);
console.log(v2.num);
JS関数補完
// 1) ( , )
// , ( )
// , undefined
function fn1(a,b) {
return a + b;
}
let res = fn1(10,20);
console.log(res);
// 2)
let fn2 = function (a,b) {
return a + b;
};
//
let fn3 = (a,b) => {
return a + b
};
// , , {}, , return
let fn4 = (a,b) => a + b;
console.log(fn4(11,22));
// , ()
let fn5 = num => num * num;
console.log(fn5(3));
// js
console.log(10 + '5'); // 105
console.log(10 - '5'); // 5
console.log(+'55555'); // 55555