Why ng new newApp producing unable to resolve dependency tree error

Question

I am trying to create a new angular app using the command ng new app-name.. But after running the command, it is showing the following in the command line.

Installing packages (npm)...npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! node_modules/jasmine-core
npm ERR!   dev jasmine-core@"~3.6.0" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer jasmine-core@">=3.7.1" from [email protected]
npm ERR! node_modules/karma-jasmine-html-reporter
npm ERR!   dev karma-jasmine-html-reporter@"^1.5.0" from the root project
npm ERR! 
npm ERR! 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.
npm ERR! 
npm ERR! See /home/vazha/.npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/vazha/.npm/_logs/2021-05-07T05_12_55_121Z-debug.log
✖ Package install failed, see above.
The Schematic workflow failed. See above.

How can we fix this issue?

Answer 1

This error is caused by an npm 7 issue. The Angular team recommends to use npm 6 for now.

Run npm install -g npm@6 to ensure that you are using that version.

An alternative can be to run ng new with the --skipInstall flag, and then install the dependencies with npm install --legacy-peer-deps.

Answer 2

First create the project as usual:

ng new <project>

Then go to the project directory and change version of jasmine-core in package.json to "^3.7.1". Then start install again:

npm install

This is a temporary solution but it works