How do I fix the npm UNMET PEER DEPENDENCY warning?

六月ゝ 毕业季﹏ 提交于 2019-11-26 12:44:47

npm no longer installs peer dependencies so you need to install them manually, just do an npm install on the needed deps, and then try to install the main one again.


Reply to comment:

it's right in that message, it says which deps you're missing

UNMET PEER DEPENDENCY angular-animate@^1.5.0 +-- 
UNMET PEER DEPENDENCY angular-aria@^1.5.0 +-- angular-material@1.0.6 +
UNMET PEER DEPENDENCY angular-messages@^1.5.0 `-- mdi@1.4.57` 

So you need to npm install angular angular-animate angular-aria angular-material angular-messages mdi

JayKrish

UNMET PEER DEPENDENCY error is thrown when the dependencies of one or more modules specified in the package.json file is not met. Check the warnings carefully and update the package.json file with correct versions of dependencies.

Then run

rm -rf node_modules/
npm cache clean
npm install

This will install all the required dependencies correctly.

Anuj Sharma

In my case all the dependencies were already there. Please update NPM in that case as it might have been crashed. It solved my problem.

npm install -g npm
alexoviedo999

npm-install-peers worked for me.

npm install -g npm-install-peers

One of the most possible causes of this error could be that you have defined older version in your package.json. To solve this problem, change the versions in the package.json to match those npm is complaining about.

Once done, run npm install and voila!!.

Ok so i struggled for a long time trying to figure this out. Here is the nuclear option, for when you have exhausted all other ways..

When you are done, and it still works, import your actual code into this new project. Fix any compile errors the newer version of angular causes.

Thats what did it for me.. 1 hour of rework vs 6 hours of trying to figure out wtf was wrong.. wish i did it this way to start..

Today available Angular 2 rc.7, and I had a similar problem with rxjs@5.0.0-beta.12 UNMET PEER DEPENDENCY.

If you, like me, simply replaced @angular/...rc.6 to @angular/...rc.7 - it's not enough. Because, for example, @angular/router has no rc.6 version.

In this case, better review package.json in Quick start

This answer doesn’t apply all cases, but if you can’t solve the error by simply typing npm install , this steps might help.

Let`s say you got this error.

UNMET PEER DEPENDENCY packageA@4.2.0

npm WARN packageB@3.3.0 requires a peer of packageA@^3.1.0 but none was installed.

This means you installed version 4.2.0 of packageA, but packageB@3.3.0 needs version 3.x.x of pakageA. (explanation of ^)

So you can resolve this error by downgrading packageA to 3.x.x, but usually you don`t want to downgrade the package.
Good news is that in some cases, packageB is just not keeping up with packageA and maintainer of packageB is trying hard to raise the peer dependency of packageA to 4.x.x.
In that case, you can check if there is a higher version of packageB that requires version 4.2.0 of packageA in the npm or github.

For example, Go to release page

Oftentimes you can find breaking change about dependency like this.

packageB v4.0.0-beta.0

BREAKING CHANGE
package: requires packageA >= v4.0.0

If you don’t find anything on release page, go to issue page and search issue by keyword like peer. You may find useful information.

At this point, you have two options.

1) Upgrade to the version you want
2) Leave error for the time being, wait until stable version is released.

If you choose option1:
In many cases, the version does not have latest tag thus not stable. So you have to check what has changed in this update and make sure anything won`t break.

If you choose option2:
If upgrade of pakageA from version 3 to 4 is trivial, or if maintainer of pakageB didn’t test version 4 of pakageA yet but says it should be no problem, you may consider leaving the error.

In both case, it is best to thoroughly test if it does not break anything.

Lastly, if you wanna know why you have to manually do such a thing, this link explains well.

The given answer wont always work. If it does not fix your issue. Make sure that you are also using the correct symbol in your package.json. This is very important to fix that headache. For example:

warning " > @angular/compiler-cli@5.2.7" has incorrect peer dependency "typescript@>=2.4.2 <2.7".
warning " > tsickle@0.25.6" has incorrect peer dependency "typescript@>=2.4.2 <2.6".

So my typescript needs to be between 2.4.2 and 2.6 right?

So I changed my typescript library from using "typescript": "^2.7" to using "typescript": "^2.5". Seems correct?

Wrong.

The ^ means that you are okay with npm using "typescript": "2.5" or "2.6" or "2.7" etc...

If you want to learn what the ^ and ~ it mean see: What's the difference between tilde(~) and caret(^) in package.json?

Also you have to make sure that the package exists. Maybe there is no "typescript": "2.5.9" look up the package numbers. To be really safe just remove the ~ or the ^ if you dont want to read what they mean.

you can resolve by installing the UNMET dependencies globally.

example : npm install -g @angular/common@4.4.6

install each one by one. its worked for me.

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