试试这个，它在macOS上运行良好:

$ brew uninstall --force yarn
$ npm uninstall -g yarn
$ yarn -v

V0.24.5(或当前版本)

$ which yarn

/usr/local/bin/yarn

$ rm -rf /usr/local/bin/yarn
$ rm -rf /usr/local/bin/yarnpkg
$ which yarn

找不到纱线

$ brew install yarn 
$ brew link yarn
$ yarn -v

V1.17.3(最新版本)

或者你可以在网站(https://classic.yarnpkg.com/lang/en/docs/install/#mac-stable)上通过npm安装它，使用:

$ npm install --global yarn

ng set——global packageManager=npm或ng set——global packageManager=yarn

Windows:

我需要做这些步骤，以完全去除纱线从系统。

Go to add or remove programs and then search for yarn and uninstall it(if you installed it with the .msi) npm uninstall -g yarn (if you installed with npm) Remove any existing yarn folders from your Program Files (x86) (Program Files (x86)\Yarn). Also need to delete your Appdata\local\yarn folder ( type %LOCALAPPDATA% in the run dialog box (win+R), it opens a local folder and there you'll find the yarn folder to delete) Finally,check your user directory and remove all .yarn folder, .yarn.lock file, .yarnrc etc ( from C:\Users\<user>\)

试试这个，它在macOS上运行良好:

$ brew uninstall --force yarn
$ npm uninstall -g yarn
$ yarn -v

V0.24.5(或当前版本)

$ which yarn

/usr/local/bin/yarn

$ rm -rf /usr/local/bin/yarn
$ rm -rf /usr/local/bin/yarnpkg
$ which yarn

找不到纱线

$ brew install yarn 
$ brew link yarn
$ yarn -v

V1.17.3(最新版本)

或者你可以在网站(https://classic.yarnpkg.com/lang/en/docs/install/#mac-stable)上通过npm安装它，使用:

$ npm install --global yarn

在windows的情况下，执行npm uninstall -g yarn后，仍然如果yarn没有卸载，然后转到“C:\Users\username\AppData\Local”并删除yarn文件夹。

关闭cmd并重新打开cmd并执行yarn。它会告诉你“yarn”不是内部或外部命令、可操作程序或批处理文件。

只要复制这个命令，您的问题就会得到解决。

NPM脱纱