Improve (speed up) build.dev.watch task

[mpetkov]

First off I wanted to say how much I love this seeder. It is very easy to use and follow. One possible improvement that I could suggest would speed up the build.dev.watch task. Currently, no matter what file changes, the entire dev destination gets rebuilt from scratch. So that means that, on average, each change takes about 10-15 seconds to complete. It would be faster if the watch was separated out so that it only updates files that were changes, instead of the whole directory. So if I change something on a css/sass file, only that file should compile and the others (such as build.js.dev) should not. This will make previewing in dev environment faster and less painful.

[joshwiens]

The change after the initial watch takes ~2.5 seconds, there was another discussion around this #496

The typescript build is incremental, an incremental build for things like css probably wouldn't be viable if you think about preprocessors ( which are supported ).

Rebuilding everything is the simple solution, rebuilding what changed is certainly possible but I'd have to tinker with it to see if it could be done in a way which can be generic enough for the seed tools.

Perhaps a possible feature after the cli project is finished.

//cc @mgechev @ludohenin

[mpetkov]

Thank you for the answer. Looks like from your comment in #496 node V5 is way faster than V4 (which I am using). In addition, when I have time I will try to separate the watchers so that they only happen per type so that if a css/html/whatever change happens, the typescript rebuild (which is the most time consuming) doesn't trigger.

[mgechev]

@mpetkov it will be great if you can help with this! Let me know what you find for node 5 vs 4, for your specific case.

[joshwiens]

@mgechev - Node 5 is definitely faster than 4.

• Mid 2014 ( 16gb + SSD )
• Fresh checkout of the angular2-seed

Node 4.4.0

Average of 5 runs dropping highest and lowest
Initial build.js.dev - 6.5s
Watch build.js.dev - 4.1s

Node 5.9.0

Average of 5 runs dropping highest and lowest
Initial build.js.dev - 4.1s
Watch build.js.dev - 1.8s

That said, on larger projects, those numbers obviously jump up. Rebuilding only what's needed in dev would be a solid change imo

[mpetkov]

@mgechev - Unfortunately my work hasn't approved Node 5 so I am unable to install it on my work machine. Here are my numbers on the latest version of node I am able to install:

Node 4.3.2:
Machine Specs: Windows 7; 8GB Ram; 2.6ghz i7-5600U
Current project size of src folder: 59 folders (110 Files) (will grow by about 2x or 3x by time its finished)

Average of 5 runs:
Initial build.js.dev - 12.67s
Watch build.js.dev - 10.47s

As noted by @d3viant0ne it would be a great addition/update to rebuild in dev only what has been changed.

[mgechev]

@mpetkov yes, sounds like terrible benchmarks.

I have a few other things in my schedule so I can schedule the optimization next weekend/the end of the week. If you have any ideas you're welcome to open a PR before that!

[joshwiens]

@mpetkov - Curious, does that system have a SSD or some sort of hybrid traditional mobile hard disk?

[mpetkov]

@d3viant0ne - It is a 256GB SSD (L8T-256L9G-HH).

[brian428]

I think part of the issue is that the watch triggers build.dev, which includes clean.dev. So I think the output folder is getting blown away after each change. I'm not sure if it's possible, but ideally the clean would only delete the files (or folders) affected by the change? Or, it might be worth considering whether a clean is actually needed during watch changes? I can see it being desired during startup, but I'm wondering if doing it for each change has more drawbacks than benefits?

[brian428]

Hmm no...just testing it by removing clean from the sequence didn't seem to affect the watch duration.

[joshwiens]

@brian428 - As an aside, rxjs5 beta.3 speeds up the watch task a bunch. I'll have it updated in the seed shortly.

[brian428]

I see you updated the RxJS dep to beta.3, but this seems to fail since Angular 2 still forces beta.2 as a peer dependency. Is there some trick I'm missing that will bypass that error?

[StefanKoenen]

Any progress on this? It would be really nice if single files are linted / compiled, a big performance hit atm compared to other seeds.

[ludohenin]

If performance is really bad with TS it's still possible to compile the tools, npm run gulp -- build.tools and npm run gulp -- clean.tools when developing tools.