Spaces in project names are not handled properly

[wojtekmaj]

Description

create-react-app allows you to create an app with spaces (and uppercase letters). Simply fire create-react-app "Example project" and it will be created! This, however, creates some issues stated below.

Expected behavior

• create-react-app should disallow creating apps with spaces and uppercase letters

OR

• create-react-app should detect if there are spaces/uppercase letters in project name provided by the user and:
  • Success message after creating an app should wrap project name in quotes if necessary
  • Project name in package.json should have spaces changed to dashes to avoid npm error

Actual behavior

After the app is created using the command above, a help message is displayed suggesting to go to the folder created by create-react app (sorry, don't remember it word-by word):

> App created successfully (...)
> Run the following command:
> cd **{project_name_here}**

Obviously, running command like cd ./My project won't work (we need to use command like cd "./My project").

Furthermore, running the app fails as the name containing spaces is also inserted into package.json file, and npm throws an error.

[Timer]

Nice catch! We would greatly appreciate if you could pull together a PR fixing this.
I believe I like the section option more, automatically replacing spaces with dashes and lowercasing.

[gaearon]

We should probably replace all unsafe characters and not just spaces.

[johann-sonntagbauer]

Its kinda tricky to provide a generic escaping mechanism because the project name has some requirements to be met. Maybe a simple validation step based on https://github.com/npm/validate-npm-package-name during creation is sufficient enough.

[gaearon]

Fixed by #1662.