1)数组Arrays
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console.log([][Symbol.iterator])
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for(let x of ['a','b'])
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console.log(x)
2)字符串Strings
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console.log(""[Symbol.iterator])
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for(let x of "abc")
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console.log(x)
3)Map
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let map = new Map().set('a', 1).set('b', 2);
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console.log(map[Symbol.iterator]);
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for (let pair of map) {
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console.log(pair);
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}
4)Set
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let set = new Set().add('a').add('b');
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for (let x of set) {
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console.log(x);
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}
5)arguments
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function printArgs() {
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for (let x of arguments) {
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console.log(x);
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}
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}
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printArgs('a', 'b');
6)Typed Arrays
7)Generators,后面讲这个的时候在介绍
然后我们在看看哪些操作符以及表达式中可以操作迭代器
1)数组解构操作符
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let set = new Set().add('a').add('b').add('c');//Chrome浏览器不支持这段代码
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let [x,y] = set;
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let [first, ...rest] = set;
2)for-of循环
3)Array.from,新添加的数组静态方法
Array.from(new Map().set(false, 'no').set(true, 'yes'))
4)spread操作符
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let arr = ['b', 'c'];
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['a', ...arr, 'd']
5)Map,Set构造函数
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let map = new Map([['uno', 'one'], ['dos', 'two']]);
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let set = new Set(['red', 'green', 'blue']);
6)Promise.all,Promise.race参数
7)yield*,后面Generators章节中讲