# JS 迴圈與效能


### JS 常見的 for 迴圈

以下由執行速度的快到慢排序

- for-loop-cached

```JS {hl_lines=[1]}
const listSize = yourList.length; // 精華
for (let index = 0; index < listSize; index++) {
  // ...
}
```

- for-loop

```JS
for (let index = 0; index < yourList.length; index++) {
  // ...
}
```

- forEach

```JS
yourList.forEach((element) => {
  // ...
});
```

- for-of

```JS
for (const element of yourList) {
  // ...
}
```

### 參考資料

[https://dev.to/siddiqus/which-for-loop-is-the-fastest-in-javascript-4hdf](https://dev.to/siddiqus/which-for-loop-is-the-fastest-in-javascript-4hdf)


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> 作者: [Admin](https://free.is-cool.dev/about)  
> URL: https://free.is-cool.dev/posts/js-foreach/