fix: algorithm for determine the end of build in watch mode

[nnecec]

if we print console.log(startTime, watcherCount) in end function, it looks like:

❯ bunchee -w
Watching project /Users/nnecec/Github/bunchee...
523.054045021534 1
523.054045021534 2
523.054045021534 3
523.054045021534 4
✓ Build in 3250.67ms
523.054045021534 5
523.054045021534 6
523.054045021534 7
523.054045021534 8
523.054045021534 9
523.054045021534 10

logWatcherBuildTime will be executed only once at the beginning. So we need reset startTime and watcherCount in the start function.

Also, if we modify a file, it may not trigger a rebuild of all the entry files, so the watcherCount maybe not equal to result.length.

[huozhi]

Will this have concurrence issue? Last time I checked the number it's shorter than the actual build time

[nnecec]

How to reproduce the concurrence issue?

[huozhi]

You can log all the build duration and compare

[nnecec]

Take bunchee as an example, when I run the command pnpm bunchee -w in the project, it will start 4 jobs, watcherCounter will increase to 4 and then decrease to 0 one by one. After I modify bundle.js and saved, it will restart 2 jobs, watcherCounter will increase to 2 and then decrease to 0.

[huozhi]

I was testing against multi-entries integration test, it has more jobs spinning up together. Is that one also logging the same data for you?

[nnecec]

I tried in multi-entries test, still feel good.

Here are steps:

1. open bunchee project, execute pnpm build, pnpm install, npm link in turn.
2. cd test/integration/multi-entries, execute bunchee -w
3. modify some files and saved.

Here is a sample:

bunchee -w
Watching project /Users/nnecec/Github/bunchee/test/integration/multi-entries...
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✓ Build in 7681.08ms
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✓ Build in 1155.92ms
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✓ Build in 761.12ms
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✓ Build in 2460.70ms

[huozhi]

sounds good, let's ship it, thanks!