# React 支援舊版本瀏覽器問題

###### tags: `React` `debug` `browser`
不知道多舊版的 win chrome 出現的錯誤：
:::danger
TypeError: Object.entries is not a function
:::

遇到版本問題第一個想法就是 `polyfill`
查了一下 React polyfill 套件: `react-app-polyfill`，使用 `create-react-app` 安裝的裡面就有含了

### step.1
`package.json` 新增 `'ie 11'`

"browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all",
      "ie 11"                 >>> 多加
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version",
      "ie 11"                 >>> 多加
    ]
}

### step.2
`index.js` 入口檔案最上層加上

import 'react-app-polyfill/ie11'
import 'react-app-polyfill/stable'

目前還沒遇到 IE 死掉的狀況
只有測到舊版 chrome，然後以上兩步驟加完也正常了
### 線上舊版 win chrome 載點 [點我GO](https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/Win_x64%2F389347%2Fmini_installer.exe?generation=1461381229389000&alt=media)

### Reference:
https://stackoverflow.com/questions/59834690/react-app-polyfill-doesnt-work-in-ie11
https://dotblogs.com.tw/wasichris/2019/06/20/234252
https://github.com/facebook/create-react-app/issues/8195
https://create-react-app.dev/docs/supported-browsers-features/#configuring-supported-browsers