String.prototype[Symbol.iterator]()

¥Syntax

string[Symbol.iterator]()

¥Parameters

没有任何。

¥None.

¥Return value

一个新的 可迭代的迭代器对象，它将字符串值的 Unicode 代码点生成为单独的字符串。

¥A new iterable iterator object that yields the Unicode code points of the string value as individual strings.

¥Description

字符串通过 Unicode 代码点进行迭代。这意味着字素簇将被分割，但代理对将被保留。

¥Strings are iterated by Unicode code points. This means grapheme clusters will be split, but surrogate pairs will be preserved.

// "Backhand Index Pointing Right: Dark Skin Tone"
[..."👉🏿"]; // ['👉', '🏿']
// splits into the basic "Backhand Index Pointing Right" emoji and
// the "Dark skin tone" emoji

// "Family: Man, Boy"
[..."👨‍👦"]; // [ '👨', '‍', '👦' ]
// splits into the "Man" and "Boy" emoji, joined by a ZWJ

¥Examples

¥Iteration using for...of loop

请注意，你很少需要直接调用此方法。[Symbol.iterator]() 方法的存在使得字符串 iterable，像 for...of 循环这样的迭代语法会自动调用该方法来获取要循环的迭代器。

¥Note that you seldom need to call this method directly. The existence of the [Symbol.iterator]() method makes strings iterable, and iterating syntaxes like the for...of loop automatically call this method to obtain the iterator to loop over.

const str = "A\uD835\uDC68B\uD835\uDC69C\uD835\uDC6A";

for (const v of str) {
  console.log(v);
}
// "A"
// "\uD835\uDC68"
// "B"
// "\uD835\uDC69"
// "C"
// "\uD835\uDC6A"

¥Manually hand-rolling the iterator

你仍然可以手动调用返回的迭代器对象的 next() 方法，以实现对迭代过程的最大控制。

¥You may still manually call the next() method of the returned iterator object to achieve maximum control over the iteration process.

const str = "A\uD835\uDC68";

const strIter = str[Symbol.iterator]();

console.log(strIter.next().value); // "A"
console.log(strIter.next().value); // "\uD835\uDC68"

¥See also

• core-js 中 String.prototype[Symbol.iterator] 的 Polyfill
• 文本格式 指南
• Symbol.iterator
• 迭代协议