88 lines
1.8 KiB
Markdown
88 lines
1.8 KiB
Markdown
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---
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title: For...Of Loop
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localeTitle: 对于...... Of Loop
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---
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`for...of`语句创建循环遍历可迭代对象（包括Array，Map，Set，Arguments对象等），调用自定义迭代挂钩，其中包含要为每个不同属性的值执行的语句。
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```javascript
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for (variable of object) {
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statement
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}
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```
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| |说明| | ---------- | ------------------------------------- | |变量|在每次迭代时，将不同属性的值分配给变量。 | |对象|迭代其可枚举属性的对象。 |
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## 例子
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### 排列
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```javascript
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let arr = [ "fred", "tom", "bob" ];
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for (let i of arr) {
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console.log(i);
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}
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// Output:
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// fred
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// tom
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// bob
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```
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### 地图
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```javascript
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var m = new Map();
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m.set(1, "black");
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m.set(2, "red");
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for (var n of m) {
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console.log(n);
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}
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// Output:
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// 1,black
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// 2,red
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```
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### 组
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```javascript
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var s = new Set();
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s.add(1);
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s.add("red");
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for (var n of s) {
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console.log(n);
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}
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// Output:
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// 1
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// red
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```
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### 参数对象
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```javascript
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// your browser must support for..of loop
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// and let-scoped variables in for loops
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function displayArgumentsObject() {
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for (let n of arguments) {
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console.log(n);
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}
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}
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displayArgumentsObject(1, 'red');
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// Output:
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// 1
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// red
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```
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# 其他资源：
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* [MDN链接](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Statements/for…of)
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* [MSDN链接](https://msdn.microsoft.com/library/dn858238%28v=vs.94%29.aspx?f=255&MSPPError=-2147217396)
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* [参数@@ iterator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments/@@iterator)
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