Support templates in scoped packages

[klasbj]

Fixing issue #7985.

I learned a bit about some... interesting... NPM behavior while testing. With only a regex check that the package name started with cra-template-, it still fell back to cra-template-@scope/package. If scope/package happened to be an accessible Github project, npm would download and install some version (I'm not quite sure how it decided which version...) of that repository as the template.

The solution I came up with was adding the prefix to the package name, while leaving the scope part unchanged. Maybe not 100% intuitive, but consistent with the behaviour of non-scoped packages.

Test cases

Plain, uses cra-template

CRA_INTERNAL_TEST=1 yarn create-react-app my-app1
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app1.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with cra-template...
# [...]

Template without prefix (typescript), uses cra-template-typescript

CRA_INTERNAL_TEST=1 yarn create-react-app --template typescript my-app2
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app2.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with cra-template-typescript...
# [...]

Template with prefix (cra-template-typescript)

CRA_INTERNAL_TEST=1 yarn create-react-app --template cra-template-typescript my-app3
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app3.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with cra-template-typescript...
# [...]

Template in scoped npm package with prefix (@klasbj/cra-template-scoped)

CRA_INTERNAL_TEST=1 yarn create-react-app --template "@klasbj/cra-template-scoped" my-app4
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app4.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with @klasbj/cra-template-scoped...
# [...]

Template in scoped npm package without prefix (@klasbj/scoped), uses @klasbj/cra-template-scoped

CRA_INTERNAL_TEST=1 yarn create-react-app --template "@klasbj/scoped" my-app5
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app5.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with @klasbj/cra-template-scoped...
# [...]

Scoped template with matching Github project, attempts to use @klasbj/cra-template-scoped-cra-template, and not my Github project klasbj/scoped-cra-template

CRA_INTERNAL_TEST=1 yarn create-react-app --template "@klasbj/scoped-cra-template" my-app6
# [...]
# Creating a new React app in /home/klasse/projects/create-react-app/my-app6.
#
# Installing packages. This might take a couple of minutes.
# Installing react, react-dom, and react-scripts with @klasbj/cra-template-scoped-cra-template...
#
# [1/4] Resolving packages...
# error An unexpected error occurred: "https://registry.yarnpkg.com/@klasbj%2fcra-template-scoped-cra-template: Not found".
# info If you think this is a bug, please open a bug report with the information provided in "/home/klasse/projects/create-react-app/my-app6/yarn-error.log".
# info Visit https://yarnpkg.com/en/docs/cli/add for documentation about this command.
#
# Aborting installation.
#   yarnpkg add --exact react react-dom /home/klasse/projects/create-react-app/packages/react-scripts/react-scripts-3.2.0.tgz @klasbj/cra-template-scoped-cra-template --cwd /home/klasse/projects/create-react-app/my-app6 has failed.
#
# Deleting generated file... package.json
# Deleting generated file... yarn.lock
# Done.
# [...]

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[mrmckeb]

Thanks @klasbj, this looks great.

[mrmckeb]

Thanks again!