Add a "watch" command

[Jujulego]

The idea is to behave like the "run" command, but instead of ending when all task are done, this should watch over input files, and retrigger tasks affected by detected changes, and then retrigger dependent tasks.

Problems:

• Detecting "input files" in a generic way, to keep configuration to a minimum
• Supporting "watch modes". Many build tools (tsc, webpack, vite, rollup, etc...) already have a watch ability, providing optimizations (not rebuild all files) and dev friendly functionalities (hot reload):
  • Detect those tools (maybe use the "watch" script if available and fallback to "build" script)
  • Detect when they end their work, to trigger dependent tasks. Retriggering them should not be needed as they should watch over output of previous task

[Jujulego]

To detect : use .gitignore file => all that is not ignored might be a source file + override by a property in workspace's package.json

[Jujulego]

Rollup integration (and vite) : can develop a plugin, using buildStart & buildEnd to monitor rollup build state.

buildStart can return a Promise (might allow to control start if rollup waits for it to resolve)

Rollup plugin doc

[Jujulego]

Webpack integration : can develop a plugin, using beforeRun & done to monitor webpack state.

beforeRun is async & serial => might allow to control compilation start

Webpack compile hooks