How can I initiate watch mode with ngc?

Question

I would like to do the same, as I could in the good old tsc times: simply calling a tsc -w, and in the case of a changed file, it will be on the fly recompilated.

Unfortunately, ngc doesn't even seem to react anything to the -w flag, and even its possible command line arguments are completely undocumented.

But, ng build has a --watch flag, while it can create also AOT builds. Thus, probably a watch-mode ngc is possible.

But how?

@Maximus Ok, but why angular-cli still supports it, while it supports also aot? — peterh, Jun 07 '17 at 15:41
I don't know. The recent talk I watched by Tobias about future plans included supporting watch mode for `ngc`, hence it doesn't support it now — Max Koretskyi, Jun 07 '17 at 15:48
@Maximus Could you please insert a link to this talk as an answer converted from your comment? I would be happy to upvote/accept it. Thanks! — peterh, Jun 07 '17 at 16:12
sure, done, thanks. I've recently written [an article](https://hackernoon.com/here-is-what-you-need-to-know-about-dynamic-components-in-angular-ac1e96167f9e) that touches upon a compiler a bit. Might be of interest to you — Max Koretskyi, Jun 07 '17 at 16:18

Max Koretskyi · Answer 1 · 2017-11-30T17:46:46.073

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Version 5:

You can now use watch mode like this:

ngc -w

See this comment by Tobias:

The command line ngc also has a -w option now that watches the file system and we see speedups for subsequent builds of up to 10x, as we have some logic in place to only compile components in node_modules 1x.

Version prior to 4

At the moment ngc doesn't support watch mode. It's addition identified by the Tobias Bosch as priority features. Here is the video where he talks about that.

edited Nov 30 '17 at 17:46

answered Jun 07 '17 at 16:16

Max Koretskyi

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This answer is valid until Angular4. From Angular5, see the other answer. – peterh Nov 30 '17 at 17:39
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@peterh, there was no need to undo an accept, I could have just updated the answer. I have, anyways – Max Koretskyi Nov 30 '17 at 17:47

score 1 · Accepted Answer · answered Nov 08 '17 at 11:30

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The changelog of Angular 5 states that ngc watch is now a thing! https://github.com/angular/angular/blob/master/CHANGELOG.md#500-pentagonal-donut-2017-11-01

Features: compiler-cli: add watch mode to ngc (#18818) (06d01b2)

answered Nov 08 '17 at 11:30

kair

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This answer is valid only from angular5. Until angular4, see the other answer. – peterh Nov 30 '17 at 17:39

How can I initiate watch mode with ngc?

2 Answers2

Version 5:

Version prior to 4