Checkjs implies allowjs

[Nathan Shively-Sanders (sandersn)]

If it's not explicitly provided.

Note that it's still an error to explicitly provide checkJs: true, allowJs: false.

This change makes the compiler options easier to use and to describe.

[Nathan Shively-Sanders (sandersn)]

Daniel Rosenwasser (@DanielRosenwasser)Ryan Cavanaugh (@RyanCavanaugh)Orta Therox (@orta) Do you think the new behaviour is reasonable?

Sheetal Nandi (@sheetalkamat)Wesley Wigham (@weswigham) Is createProgram the right place to put this?

[Wesley Wigham (weswigham)]

For other defaulted flags dependent on other flags, we have something like a getStrictCompilerOptionValue helper that we use everywhere rather than checking the compiler options directly (no, I don't think createProgram handles all inputs - transpileModule is notable for probably being unaffected). You should probably add a getAllowJSCompilerOption helper that we use everywhere rather than checking the flags directly.

[Nathan Shively-Sanders (sandersn)]

I thought that might be the case. I switched to an accessor function getAllowJSCompilerOption instead.

[Sheetal Nandi (sheetalkamat)]

This seems incorrect condition. You want to check if options.allowJs === false here instead

[Nathan Shively-Sanders (sandersn)]

Duh, thanks for the catch.

[Nathan Shively-Sanders (sandersn)]

No, wait, that undoes the loosening from this PR. THe current code only errors when checkJs: true but allowJs: false explicitly.

[ExE Boss (ExE-Boss)]

Suggested change

	if(options.checkJs&&!getAllowJSCompilerOption(options)){
	if(options.checkJs&&options.allowJs===false){

will also work and won’t require a function call.

[Daniel Rosenwasser (DanielRosenwasser)]

I'm not so sure how I feel about this. But I can't think of any reason why it's bad.

[Nathan Shively-Sanders (sandersn)]

Chatted with Ryan Cavanaugh (@RyanCavanaugh), he couldn't either.

He also pointed out that maybe allowJs should default to true now. I'll investigate that next.