Use node watch mode when watch is enabled to restart the application when dependencies change

[hartbit]

PR Checklist

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)

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PR Type

What kind of change does this PR introduce?

[X] Bugfix
[X] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

This is in-between a bugfix and a new feature: I was expecting the watch mode of Nest.js to behave like nodemon or Node.js' watch mode and watch all imported files, and not like TypeScript's build watch that only watches files to build.

What is the current behavior?

Currently, the start command's watch mode only watches for files to build. But once the application has started, changes to dependencies don't trigger a restart. It's a build watch, not a run watch.

What is the new behavior?

This change appends the --watch option to the node command run when the build succeeds to also add this run watch behaviour.

Does this PR introduce a breaking change?

[ ] Yes
[X] No

[micalevisk]

It's a build watch, not a run watch.

yeah. Not sure if we really want to switch to a run watch, tho

it could be resource consuming. In the build watch approach we can optimize this

[hartbit]

@micalevisk Any news on potentially merging this ? How can I resolve your worries to move this forward ?