const alpha=["A","BB",'c'];
const lan=['php','go','js'];
//中間插入java
let members=[];
members=members.concat(alpha)
members.push('java')
members=members.concat(lan)
//使用擴展做法
const newMembers=[...alpha,'java',...lan]
console.log([...'php']) //array
//等同下面的
console.log(Array.from('php')) //array
數組的複製
const alpha=["A","BB",'c'];
// const curAlpha=alpha;
// curAlpha[0]='aaa'; //導致alpha的值也會改變
const newAlpha=[...alpha]
newAlpha[0]='a' ;//alpha沒被改變
擴展運算符在函數參數裏運用
const fruit=['apple','bananas','pear']
const newFruit=['orange','mongo'];
//把兩者合併有不產生新的數組
// fruit.push.apply(fruit,newFruit) //fruit改變了
//或者在ES6裏
fruit.push(...newFruit)
- 屬性名和變量名相同時的對象賦值省略key
- 對象字面量了的方法定義簡寫
const name='hk'
const age=29;
const sex=1;
//當屬性名和變量同名時
const person={
name,
age,
sex
}
//方法簡寫
const anmimal={
name,
age,
greet(){
console.log(`${this.name} say hello`)
},
getName(){
console.log(`${this.name}`)
}
}
let id=0;
const userIds={
[`user-${++id}`]:id,
[`user-${++id}`]:id,
[`user-${++id}`]:id
}
const keys=['name','age','birthday']
const values=['hk',2,'2020-01-01'];
const p={
[keys.shift()]:values.shift(),
[keys.shift()]:values.shift(),
[keys.shift()]:values.shift(),
}