his is probably not a problem with npm. There is likely additional logging output above.npm WARN Local package.json exists, but node_modules missing, did you mean to install? code example

Example 1: This is probably not a problem with npm. There is likely additional logging output above.

npm  run build -prod

Example 2: node_modules missing did you mean to install

npm start runs a script that the app maker built for easy starting of the app npm install installs all the packages in package.json

run npm install first

then run npm start

Example 3: This is probably not a problem with npm. There is likely additional logging output above.

node --max_old_space_size=4096 node_modules/@angular/cli/bin/ng build --prod