npm install出现npm ERR! code ERESOLVE npm ERR! ERESOLVE could not resolve

PS E:\myvue\bookshop> npm i
npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: @vue/eslint-config-standard@6.1.0
npm ERR! Found: eslint-plugin-vue@8.7.1
npm ERR! node_modules/eslint-plugin-vue
npm ERR!   dev eslint-plugin-vue@"^8.0.3" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer eslint-plugin-vue@"^7.0.0" from @vue/eslint-config-standard@6.1.0
npm ERR! node_modules/@vue/eslint-config-standard
npm ERR!   dev @vue/eslint-config-standard@"^6.1.0" from the root project
npm ERR!
npm ERR! Conflicting peer dependency: eslint-plugin-vue@7.20.0
npm ERR! node_modules/eslint-plugin-vue
npm ERR!   peer eslint-plugin-vue@"^7.0.0" from @vue/eslint-config-standard@6.1.0
npm ERR!   node_modules/@vue/eslint-config-standard
npm ERR!     dev @vue/eslint-config-standard@"^6.1.0" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.

只要在npm install后面加上--legacy-peer-deps就可以解决问题

PS E:\myvue\bookshop> npm i --legacy-peer-deps
npm WARN deprecated stable@0.1.8: Modern JS already guarantees Array#sort() is a stable sort, so this library is deprecated. See the compatibility table on MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#browser_compatibility

added 996 packages, and audited 997 packages in 11s

1 critical severity vulnerability

原因：

npm install xxxx --legacy-peer-deps命令可以这么理解，legacy的意思：遗产/（软件或硬件）已过时但因使用范围广而难以替代的；所以npm install xxxx --legacy-peer-deps命令就是用于绕过peerDependency这个依赖的自动安装，peerDependency使得用户依赖的包版本与各个子项目依赖的包版本相互不兼容，那么就会报错（无法解析依赖树的问题（依赖冲突））让用户自行去修复，因而导致安装过程的中断。（因为是从npm v7引入的，因此npm v3-v6就不会发生这个错误）；它告诉npm忽略项目中引入的各个依赖模块之间依赖相同但版本不同的问题，以npm v3-v6的方式去继续执行安装操作。所以其实该命令并没有真的解决冲突，而是忽略了冲突，以“过时”（v3-v6）的方式进行下载操作。