您可以使用显示此错误的两种方式安装包

ERESOLVE unable to resolve dependency tree

使用npm Install并使用——legacy-peer-deps安装包

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

这是两个命令的组合 a.在npm config中设置legacy-peer-deps为true NPM配置设置为true b.现在使用npm install安装包 npm安装

以防万一，当我尝试npm升级当前的Angular 11时，我确实有类似的行为。或者基于Angular 12.x创建新的ng new abc。我只是忘了升级Angular CLI。所以这个npm install -g @angular/cli@latest解决了我在ng new abc期间的错误。

NPM可用于在项目中安装和管理依赖项的版本。

我在React版本和npm版本上也遇到了同样的问题:

NPM错误发现类型/react@16.14.20

因此，它可能是需要根据您的包安装的包版本。json文件。

它会在npm 7版本中给出错误，并且无法安装Node.js模块。

如果你将npm版本降级到6，这些问题将变成警告，问题将得到解决。

试着证明这个命令:npm install -g npm@6 检查版本是否已经安装:npm——version 删除并安装node_modules包: a)删除rm -rf node_modules b)安装:npm i

试试这个命令-

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

只需做两个简单的步骤:

首先，在终端中执行这个命令。

npm config set legacy-peer-deps true

其次，清除缓存:

npm cache clean --force

最后，执行你的命令。这肯定有用。

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.