Javascript 在npm中安装后出现角度引导错误

我已经在NPMCLI中安装了jquery、popper.js和bootstrap。安装后，我在angularcli.json中为引导添加了样式引用。当我运行项目时，会显示以下错误。请帮忙

ERROR in ./~/css-loader?{"sourceMap":false,"importLoaders":1}!./~/postcss-loader?{"ident":"postcss"}!./~/bootstrap/dist/css/bootstrap.min.css
Module build failed: BrowserslistError: Unknown browser major
    at error (C:\Users\hasan\angulartest\boottest\node_modules\browserslist\index.js:37:11)
    at Function.browserslist.checkName (C:\Users\hasan\angulartest\boottest\node_modules\browserslist\index.js:320:18)
    at Function.select (C:\Users\hasan\angulartest\boottest\node_modules\browserslist\index.js:438:37)
    at C:\Users\hasan\angulartest\boottest\node_modules\browserslist\index.js:207:41
    at Array.forEach (native)
    at browserslist (C:\Users\hasan\angulartest\boottest\node_modules\browserslist\index.js:196:13)
    at Browsers.parse (C:\Users\hasan\angulartest\boottest\node_modules\autoprefixer\lib\browsers.js:44:14)
    at new Browsers (C:\Users\hasan\angulartest\boottest\node_modules\autoprefixer\lib\browsers.js:39:28)
    at loadPrefixes (C:\Users\hasan\angulartest\boottest\node_modules\autoprefixer\lib\autoprefixer.js:56:18)
    at plugin (C:\Users\hasan\angulartest\boottest\node_modules\autoprefixer\lib\autoprefixer.js:62:18)
    at LazyResult.run (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:274:20)
    at LazyResult.asyncTick (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:189:32)
    at LazyResult.asyncTick (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:201:22)
    at processing.Promise.then._this2.processed (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:228:20)
    at LazyResult.async (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:225:27)
    at LazyResult.then (C:\Users\hasan\angulartest\boottest\node_modules\postcss\lib\lazy-result.js:131:21)
 @ ./~/bootstrap/dist/css/bootstrap.min.css 4:14-127
 @ multi ./~/bootstrap/dist/css/bootstrap.min.css ./src/styles.css

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这看起来像是某种相关的问题。
请看这个：

• 从“引导”：“^4.0.0-beta.2”到“引导”：“4.0.0-beta.2”，取出“^”
• 然后安装npm
• 然后ng发球

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来源：

引导版本4似乎有bug。我在packages.json中将引导版本从4.0.0更改为3.0.0，并运行命令npm install。在那之后一切都很好