Adds Support for Yarn Install If Supported

[benmarten]

checks if yarn is available and runs yarn install on setup. falls back to npm if yarn is not
installed.

• I have read the Contributing Documents
• My commit(s) follow the AngularJS commit message guidelines
• The generator's tests pass (generator-angular-fullstack$ npm test)

[Awk34]

we should be checking if the user is on Windows, and using the proper Windows commands if so

[benmarten]

I'm not on windows and don't have access to it atm.
I found this: https://superuser.com/questions/175466/determine-if-command-is-recognized-in-a-batch-file
Hence we could use: WHERE yarn >nul 2>nul; IF %ERRORLEVEL% EQU 0 yarn install ELSE npm install --quiet;
Can you or sb. confirm that this works please?

[Awk34]

This worked for me:

yarn --version >nul 2>&1 && ( yarn install ) || ( npm install --quiet )

We should be able to use process.platform to figure out what the user is on.

[benmarten]

Updated. Tested regular install on macOS.
Tried running: gulp installFixtures but that doesn't work.

Can you test on Windows too please?

[Awk34]

The Windows check fails, since indexOf('win') on 'win32' is 0 (falsey). Just check process.platform === 'win32' instead

[benmarten]

Gotta, I thought there might be win64, changed it to win32 now though ;)

[Awk34]

Yeah, that would make sense, but the process docs only has win32. There's a different arch property for 32 vs 64 bit.

Anyhow, your code will still not work on Windows, since process.platform.indexOf('win32') on Windows will result in 0, which is falsey and will not enter the if block.

You can either use process.platform.indexOf('win32') >= 0, or process.platform === 'win32'

[benmarten]

updated.