修改源地址时，若加上--global，则为全局设置源地址；否则，仅当前项目生效

npm

1. 查看当前源

npm config get registry

2. 修改npm源为淘宝源

npm config set registry https://registry.npm.taobao.org

3. 修改npm源为官方源

npm config set registry http://registry.npmjs.org

yarn

1. 查看当前源

yarn config get registry

2. 修改yarn源为taobao源

yarn config set registry https://registry.npm.taobao.org

3. 修改yarn源为官方源

yarn config set registry https://registry.yarnpkg.com