The Angular Compiler requires TypeScript >=2.7.2 a

Question

I starting getting this error on my Angular app:

The Angular Compiler requires TypeScript >=2.7.2 and <2.8.0 but 2.8.3 was found instead

and when I try to downgrade typescript to the right version doing:

npm install -g typescript@2.7.2 it says updated 1 package.

when I verify typescript version using npm view typescript version I still get 2.8.3

I even tried removing typescript entirely using npm uninstall -g typescript

but when I verify typescript version again npm view typescript version I still get 2.8.3

What are the commands to properly purge and restore typescript to a previous version such as 2.7.2?

I'm running node v10.0.0 and npm v6.0.1

When I run npm list -g typescript I see the correct version coming 2.7.2 but still version 2.8.3 is installed somehow globally

Answer 1

Downgrading to typescript 2.9.2 (npm install typescript@2.9.2) and re-running ng update --all still yields the error (twice):

Package "@angular/compiler-cli" has an incompatible peer dependency to "typescript" (requires ">=2.7.2 <2.10", would install "3.1.3"
Verified that version 2.9.2 of typescript was in node_modules.

Answer 2

This is just because in your projects package.json file has

eg."devDependencies": {"typescript": "~2.8.3" }

and in your machine where angular cli installed has "typescript": "2.7.2" version.

You can check this by ng -v or ng v.

So, just open package.json update your typescript version and run npm install and you are done.

Answer 3

Installing "@angular/compiler-cli": "7.0.0-beta.4" resolved this issue. I use "typescript": "3.0.3".

Answer 4

Had the same issue (amongst many others) after updating to macOS Mojave. Fixed it by removing node_modules and package_lock.json manually, changed in package.json from "typescript": "~2.7.2" to "typescript": "~2.8.0" and ran npm install.

Answer 5

To upgrade, run the following commands in the terminal.

• Install the latest version of NPM

  npm install npm@latest -g
  

• Run audit

  npm audit  
  

• Update the NPM

  npm update
  

• Run the NPM run script.

  npm start
  

Now your compiler is ready.

Answer 6

I did the following:

• Delete manually the folder node_modules
• Delete manually the file package-lock.json

• In the file package.json be sure to set the dependence of TypeScript as

   "typescript": "2.7.2"
  

• run npm cache clean -f

• run npm install

That work for me.