在使用npm 7时，这种情况经常出现，因为对等依赖问题在版本7中被视为错误，而在版本6中通常只是警告。通常使用——legacy-peer-deps可以让它在npm 7中工作。

当这不起作用时，一个选择是降级到npm 6。降级Node.js是没有必要的(但也没有害处)。相关的依赖管理代码在npm中。降级Node.js通常是巧合，因为这样做通常也会降级npm。

另一个比降级npm破坏性更小的选择是使用npx来使用之前版本的npm的install命令:npx -p npm@6 npm install

当所有这些都失败时，通常值得尝试删除node_modules目录和包锁。Json，然后再次运行NPM install。这会重新生成node_modules和package-lock.json。

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

首先我尝试了

npm install

它给了我一个错误，无法解决依赖树，根据这个命令的帮助信息，

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.

我尝试了这个命令:

npm install --legacy-peer-deps

这解决了我的问题。

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.

这是Node.js版本的问题。一些最新版本的Node.js可能会显示类似的错误。

https://github.com/nvm-sh/nvm

我使用NVM来管理系统上的Node.js版本，并使用Node.js 12来克服这个错误。

修改版本命令:

nvm use 12

在这个案子上，我遇到了问题

无法解析依赖树

在一个Angular 13项目中，它使用了Azure DevOps中私有npm提要中的一些包。

为了访问这个存储库，我创建了一个.npmrc文件。正因为如此，npm install命令将搜索我的私有存储库中的所有包，而不再是npm feed中的包。无法解决依赖树错误是因为npm install命令找不到很多托管在npm提要而不是我的私有提要中的包。

我找到了一个关于如何确定包范围的惊人答案。

在此基础上，我做了一些修改:

在我的图书馆包里。Json，更新名称有一个作用域名@mylib “名称”:“@myLib /命令队列”, 构建并将此包发布到我的私人提要 在我的客户端应用程序(使用这个包的应用程序)中，更新.npmrc文件，只对这个范围内的包使用我的私有提要 @myLib:注册表= https://pkgs.dev.azure.com/..。 always-auth = true

现在，每当我运行npm install命令时，如果包的作用域是@myLib，它就会在我的私有提要中查找它，并在所有其他情况下使用npm提要(即@angular/…)

这是我的客户端应用程序包的一个例子。json文件:

    "@angular/platform-browser-dynamic": "~13.3.0",
    "@angular/router": "~13.3.0",        <-- this comes from npm
    "@myLib/jcg-command-queue": "^2.2.0", <-- This comes from my private feed

而且，有了这个改变，就不需要再在npm install命令中添加——legacy-peer-deps了。