How does the file supervisor work?

[aleccool213]

After reading the docs, I think I have an idea of how this package should work. Please correct any wrong assumptions.

What I'm thinking this package will achieve is reduced build times locally due to yarn build understanding what has been modified. What parameters does this package consider for a module to be modified?

For example, if I have a workspace with the package user, I run yarn build and get 10 seconds (it built from scratch). But when I run it again with no code changed, I see it runs the entire build from scratch again (10 seconds). Is there a file supervisor seeing if there are any changes between the last two runs?

[ojkelly]

Currently it looks at the main script in package.json to determine the build folder.

There’s a ticket #3 is open to allow for more detailed customised options. I want to allow you to define the input and output folders for your build in package.json.

Additionally, the supervisor itself keeps a file .yarn/local-build-cache.json. This keeps track of the lastModified time of the package folder, excluding the build output.

[aleccool213]

@ojkelly

After I run yarn build, no .yarn/local-build-cache.json gets created on my local. Is that a bug?

[ojkelly]

It was renamed in a recent commit https://github.com/ojkelly/yarn.build/blob/trunk/packages/plugins/plugin-build/src/commands/supervisor/index.ts#L25 to .yarn/yarn.build.json because it contains a bunch more info.