把Node.js降级到v14适合我。

使用这些命令:

source ~/.bash_profile
nvm use v14.16.1
npm install

首先要了解问题。以下是我的错误:

npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR!
npm ERR! While resolving: project-admin@11.0.0
npm ERR! Found: @angular/common@11.0.3
npm ERR! node_modules/@angular/common
npm ERR!   @angular/common@"11.0.3" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer @angular/common@"^9.1.0 || ^10.0.0" from @agm/core@3.0.0-beta.0
npm ERR! node_modules/@agm/core
npm ERR!   @agm/core@"3.0.0-beta.0" from the root project

首先，你应该从下到上读这道题。这里@agm/core@3.0.0-beta.0需要通用的angular 9.1.0或10.0.0。最上面的消息说，角的公共发现实际上是11.0.3。

(如果你想更好地理解依赖关系，这里有一个非常简单的网站:如何npm3工作)

dependencies — these are the essential dependencies that you rely on and call in your project’s code
devDependencies — these are your development dependencies, for example, a prettier library for formatting code
peerDependencies — if you set a peer dependency in your package.json, you are telling the person who installs your package that they need that dependency with the specified version
optionalDependencies — these dependencies are optional and failing to install them will not break the installation process
bundledDependencies — it’s an array of packages that will come bundled with your package. This is useful when some 3rd party library is not on NPM, or you want to include some of your projects as modules

So what should be the solution then? The problem is about peer dependencies. The solution is to downgrade angular common or the solution is to use legacy dependencies logic for installing packages using --legacy-peer-deps. So --legacy-peer-deps does not try to install the peerDependencies automatically. Is this going to work for you? Probably, yes. But you should add specific instructions how to do that, or to make the use of --legacy-peer-deps automatic for future installation of the project packages with this code from one of the previous answers:

npm config set legacy-peer-deps true

In my case I installed the package and I tried to run ng serve, but because --legacy-peer-deps was used, there were dependency packages which were not installed. I had to install those manually (because I did not set the configuration from the code above). At the end installing about five packages manually, all with --legacy-peer-deps, I ended to a package that could not be installed and I did not try to continue, because my project was throwing warnings like crazy and there were a lot of packages for audit too. So my decision was not to use this package and to find an alternative.

我读到的其他解决方案:

downgrade Node.js to v14. This will downgrade npm. It might not be v14, but this was the version that was most widely downgraded to. Some people use Yarn to force package installation - personally I don't understand how this works, because I haven't used Yarn. downgrading Angular and the global Angular CLI version to version that will satisfy the requirement. In my case it is angular/common, and in the question it's angular/core, but both require downgrading the whole angular right (I am not sure about this here). the package you install might have a higher version that doesn't require downgrading Angular. You might try to use the https://updatepackagejson.com/ to upgrade your packages to the latest, but this is in case your project is quite new.

除了使用——legacy-peer-deps命令行选项外，还可以将其永久地设置为配置选项:

npm config set legacy-peer-deps true

这对我来说很管用:

npm install --save --legacy-peer-deps

我们有同样的问题，导致错误如下:

npm犯错!代码erresolve npm 犯错!erresolve无法解析npm 犯错! npm犯错!解析时:@angular/material-moment-adapter@12.1.4 npm 犯错!发现:@angular/material@12.0.6 npm ERR! node_modules/@angular/material@angular / material@”~ 12.0.4” 从根项目开始 .．.

我们在Azure-Pipelines中使用npm ci进行清洁安装。

问题经常出在那个包裹上。Json和包锁。Json不再同步。

解决方案是执行npm install local并推送新的package-lock.json。

作为额外的提示，我们在管道中添加了一个新任务，以便在作业失败时获得额外的信息。

 - task: Npm@1
    displayName: npm install
    inputs:
      command: custom
      customCommand: ci
      customRegistry: useNpmrc

  # ##vso[task.logissue type=error] writes the text to the summary page (error-log).
  - bash: echo "##vso[task.logissue type=error] If 'npm install' fails with 'ERESOLVE could not resolve', 'package.json' and 'package-lock.json' (needed for 'npm ci') may be out of sync. Run 'npm install' locally and push the new package-lock.json."
    condition: failed() # Only execute on fail
    displayName: npm install failed hint

Yarn有一个特性可以解决这个问题。如果可以，尝试使用它来安装包。