標籤：function epp 數字 高階函數 black else console 傳回值 i+1
Javascript中的高階函數，是我們在編程中使用的一種重要的函數式編程，它的主要形式有兩種。一種是把函數作為參數傳遞到另外一個函數中（例如：事件監聽器），另一種是把函數作為傳回值放入另外的函數中（例如：閉包函數）。
把函數作為參數傳遞的形式：
例：建立10個div並給每一個div中添加相應的數字
<body>
<div id="container">
</div>
</body>
<script>
//建立函數
function create(fn){
var container = document.getElementById(‘container‘);
for(var i=0;i<10;i++){
var div = document.createElement(‘div‘);
div.innerHTML = i+1;
container.appendChild(div);
if( typeof fn ==‘function‘){
fn(div);
}else{
console.log(‘輸入錯誤！‘)
}
}
}
//子項目添加樣式
//樣式一
function setStyle(div){
div.style.margin =‘0 auto‘;
div.style.width = ‘100px‘;
div.style.height = ‘100px‘;
div.style.background = ‘deeppink‘;
div.style.border = ‘1px solid black‘;
div.style.display = ‘inline-block‘;
}
//樣式二
function setStyle1(div){
div.style.margin =‘0 auto‘;
div.style.width = ‘50px‘;
div.style.height = ‘50px‘;
div.style.background = ‘blue‘;
div.style.border = ‘1px solid black‘;
div.style.display = ‘inline-block‘;
}
create(setStyle);
create(setStyle1);
</script>
把函數作為傳回值形式
例：利用高階函數，實現簡單的加減乘除計算機
//計算公式
function add(a,b){
return a+b;
};
function sub(a,b){
return a-b;
};
function mul(a,b){
return a*b;
};
function div(a,b){
return a/b;
};
//高階Function Compute器
function calc(fn){
return function(){
if(typeof fn == ‘function‘){
return fn.apply(this,arguments);
}
}
};
var a = calc(add)(1,2);
var b = calc(sub)(1,2);
var c = calc(mul)(1,2);
var d = calc(div)(1,2);
console.log(a);//輸出3
console.log(b);//輸出-1
console.log(c);//輸出2
console.log(d);//輸出0.5
關於js中高階函數的認識
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
