Add Vue support

[Timmmm]

This also adds a test that may or may not test anything.

Fixes #162

[mrseanryan]

(related)

• [x] @mrseanryan check what happens if more than 3 issues found -> itest should fail ...

@Timmmm about the itest not failing:

The itests use the exitWithCount option:

Set the process exit code to be the count of files that have unused exports.

So it is not counting the number of unused items - it is counting the files.

When I tried it on this branch, it worked ok (by making a copy of Math.ts)

For future - Logged #172 to improve how itests checked.

[mrseanryan]

[UPDATED - itests]

• [ ] add itest with more complex embedded Typescript.

• Mixins - standard part of TypeScript, so not needed in this PR

• [ ] @Timmmm - are there any other Vue features we need to think about?

[mrseanryan]

• [ ] add a new unit test file

The PR has an itest, but some unit tests are needed for future maintenance and debugging.

Add a new file like: vue.feature

Example:

https://github.com/pzavolinsky/ts-unused-exports/blob/master/features/base-url-undefined.feature

[Timmmm]

what about Mixins? Looks like something that could require special support.

I think mixins are a standard Typescript feature.

[FlorianWendelborn]

Since this is closed now, in case someone is still looking for a Vue compatible alternative you may want to try knip