Couldn't find package "postcss-normalize-string@^4.0.2" required by "cssnano-pre

使用 vue-cli 创建 vue3.x 版本项目报错

1、报错内容：

error Couldn't find package "postcss-normalize-string@^4.0.2" required by "cssnano-preset-default@^4.0.0" on the "npm" registry.
Error: Couldn't find package "@vue/cli-overlay@^4.5.9" required by "@vue/cli-service@~4.5.0" on the "npm" registry.
    at MessageError.ExtendableBuiltin (/usr/local/lib/node_modules/yarn/lib/cli.js:243:66)
    at new MessageError (/usr/local/lib/node_modules/yarn/lib/cli.js:272:123)
    at PackageRequest.<anonymous> (/usr/local/lib/node_modules/yarn/lib/cli.js:38988:17)
    at Generator.throw (<anonymous>)
    at step (/usr/local/lib/node_modules/yarn/lib/cli.js:92:30)
    at /usr/local/lib/node_modules/yarn/lib/cli.js:105:13
    at process._tickCallback (internal/process/next_tick.js:68:7)
 ERROR  command failed: yarn 

2、报错原因

原因：vue-cli 创建的 vue3.x 版本项目使用 yarn 进行 node_modules 包的下载，这种报错原因是本地的 yarn 版本太低

可以从报错信息上面看到 yarn 的版本是 1.9.4，升级 yarn 之后就可以了

3、解决方法

升级yarn

1. npm install yarn -g
2. brew upgrade yarn 两种升级 yarn 的方式

升级完成之后可以通过 yarn -v 查看 yarn 的版本

yarn -v
1.22.10

升级完成 重新 vue create myApp 即可