How to downgrade angular7 to angular6

You need to set the version numbers in your package.json for (at least) this packages

"@angular/animations": "^7.0.0","@angular/cdk": "7.3.3","@angular/common": "^7.0.0","@angular/compiler": "7.2.6","@angular/core": "7.2.6","@angular/forms": "^7.0.0","@angular/http": "^7.0.0","@angular/material": "7.3.3","@angular/material-moment-adapter": "^7.3.3","@angular/platform-browser": "^7.0.0","@angular/platform-browser-dynamic": "^7.0.0","@angular/router": "^7.0.0","rxjs": "6.4.0",

as well as in dev-dependencies

"@angular/compiler-cli": "^7.2.6","@angular-devkit/build-angular": "0.13.3","typescript": "3.2.4","@angular/cli": "~7.3.3",

Also make sure to downgrade every library that needs to be downgraded depending on angular's version. Check error messages after step 1...

Once you changed that, run

rm -rf node_modules

from the project's root folder to remove all packages

Then run

npm i 

And you should be good to go

I think you forgot the @ before @angular/cliTry these lines to make the change globally.

ng --versionnpm uninstall -g @angular/clinpm cache clean --forcenpm install -g @angular/cli@6.1.1ng --version

Use the same, going to your project folder, and without the -g to make the change locally.

Another way is to manually edit package.json file, remove node_modules folder and re run npm install in your project folder.