物件字面值(Object literals)
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const obj = {
name: '蘋果',
fn: function() {
return this.name;
}
}
console.log(obj.fn()); //蘋果
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縮寫後：
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const obj = {
name: '蘋果',
fn() {
return this.name;
}
}
console.log(obj.fn()); //蘋果
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物件內的變數
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const person = {
name: '小明'
};
const people = {
person: person;
}
console.log(people); //person:{ name: '小明' }
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縮寫後：
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const person = {
name: '小明'
};
const people = {
person
}
console.log(people); //person:{ name: '小明' }
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合併兩個陣列
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const groupA = ['蘋果', '香蕉', '鳳梨'];
const groupB = ['蓮霧', '芭樂'];
const groupAll = groupA.concat(groupB);
console.log(groupAll); //['蘋果', '香蕉', '鳳梨' , '蓮霧', '芭樂']
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縮寫後：
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const groupA = ['蘋果', '香蕉', '鳳梨'];
const groupB = ['蓮霧', '芭樂'];
const groupAll = [...groupA , ...groupB];
console.log(groupAll); //['蘋果', '香蕉', '鳳梨' , '蓮霧', '芭樂']
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合併兩個物件
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const methods = {
fn1() {
console.log(1);
},
fn2() {
console.log(1);
}
}
const newMethods = {
fn() {
console.log(1);
},
...methods
}
console.log(newMethods); //{fn: ƒ, fn1: ƒ, fn2: ƒ}
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將dom元素陣列轉為純陣列
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<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
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const doms = document.querySelectorAll('li');
console.log(doms); //NodeList(3) [li, li, li]
const newDoms = [...doms];
console.log(newDoms); // [li, li, li]
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純陣列比NodeList可使用的方法還多，例如：filter、map等
參數預設值
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function sum(a, b) {
if(!b){
b = 3
}
return a + b;
}
console.log(sum(1)); //4
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縮寫後：
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//設定b預設3，所以如果沒帶參數的話b自動會是3
function sum(a, b = 3) {
return a + b;
}
console.log(sum(1)); //4
//設定b預設3，但如果有真正的參數會以參數為主
function sum(a, b = 3) {
return a + b;
}
console.log(sum(1,5)); //6
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