Minor performance improvements

[deftomat]

Enable ESLint cache:
We discovered that enabling the ESLint cache can reduce the time for full rebuild. In our project, the time for a warm start decreased from 20 seconds to 17 seconds.

Disable syntactic errors check:
According to documentation, fork-ts-checker can check for syntactic errors. This is basically useless for us as Babel already report those errors.

Remove useless watch option:
According to documentation, fork-ts-checker ignores the watch option when useTypescriptIncrementalApi: true.

[eladmotola]

quick question. 2/3 of your points its about typescript users. Are those changes can affect users that dont use typescript? maybe instead of delete or change those options use the useTypeScript flag?

[deftomat]

@eladmotola Well, those 2 options are already in useTypeScript condition as they are an options of fork-ts-checker which we create only when we need to support TypeScript.

[eladmotola]

@deftomat a note to myself - check the hole file first... thank you for the answer

[deftomat]

Looks like automated tests are broken as errors are not related to these changes 😞

[ianschmitz]

Thanks for the PR @deftomat. It looks like all checkSyntacticErrors does is control whether certain messages are forwarded back to webpack from TSC: https://github.com/TypeStrong/fork-ts-checker-webpack-plugin/blob/c06ca75a7dec776881b70fe538a9368f76bfe33e/src/CompilerHost.ts#L84-L94. I don't think disabling it will net us any perf benefits is my guess.

[deftomat]

@ianschmitz Good catch. But we still don't need it as Babel will catch these issues anyway. But it is up to you, should I revert that flag?

Anyway, the only noticeable performance benefit is ESLint cache.

[ianschmitz]

Thanks! I reverted the checkSyntacticErrors change but otherwise looks good.