Add selfupdate script

[superkhau]

• Instructions posted in the Wiki

[bajtos]

I am not a big fan of Makefiles in Node projects, because they don't work on Windows. AFAIK, shelljs should make it super easy to write shell-like scripts in Node.

Also the convention is to add targets like selfupdate to package.json, so that one can run npm run selfupdate.

Last but not least, I'd like to see a command that will add all modifications to git index. This is the final user experience I have in my mind:

$ npm run selfupdate
$ git commit -m 'Update to loopback template x.y.z'
$ git push

[bajtos]

when asked for the application name, press

Please print this help message from the update script. Most people don't read docs :)

$ npm run selfupdate
Rebuilding the example. When asked for the application name, press <enter>

Another thing to consider: store the version of generator-loopback and loopback-workspace that generated the app. That's out of scope of this PR though.

[superkhau]

Please print this help message from the update script. Most people don't read docs :)

Good idea. Added. ;)

[superkhau]

@bajtos I'm having trouble executing slc loopback using shelljs (or even `child_process.exec for that matter) due to the yeoman prompt. Here is a gist: https://gist.github.com/superkhau/696826a05035c7c5e1b8

Basically gets stuck and you can't "press enter" to accept the value. Do you have a solution around this? I'm going to fall back to modifying the Makefile with the smaller items you proposed.

[superkhau]

Anyways, the current experience is pretty close to what you're saying:

$ make
$ git commit -m 'Update to loopback template x.y.z'
$ git push

is pretty close to:

$ npm run selfupdate
$ git commit -m 'Update to loopback template x.y.z'
$ git push

I am blocked on using shelljs (or child_process.exec for that matter) until we can figure out how to get "non-interactive" mode working with those libraries (ie. can't press when prompted in shelljs).

The two other things we need to decide are:

• Do we need Windows support?
  • I see it being good if we can support windows as community can help us update the repo if we provide a cross platform update script
  • However, also complicates things as we need to use a cross platform lib (such as shelljs as suggested by @bajtos, but it doesn't work ATM with the yeoman prompts)
• Should I go as far as creating the selfupdate target in package.json?
  • It's overkill IMO just to allow us to use npm run selfupdate instead of make (overkill in that I will have to write the logic to re-insert the target back into the newly scaffolded package.json)
  • I agree the npm run targets are good for usual projects, but the purpose of this project is to have a self-updating script that we (internal users) can execute easily?

@bajtos @raymondfeng @ritch Thoughts?

[bajtos]

@superkhau Based on your comments, since the effort required to rework the Makefile to shelljs script is non-trivial, it is OK to stick to Makefile. Let's not spend too much time on this.

[superkhau]

@bajtos TY, merging.

[superkhau]

Wrong button. ;p