Compile with TypeScript 1.8.10

[adidahiya]

Breaking changes in compiler APIs broke the master branch. This is a simple workaround to get compilation working, but it forces us to depend on TS 2.0 (it doesn't compile with TS 1.8).

What do you think about bumping the peer dependency @jkillian?

[alexeagle]

We had to work around this too - we compile Angular using TS 1.9 internally.
https://github.com/angular/angular/blob/979657989bab4fb93faf6a207d30760faa9bd696/tools/%40angular/tsc-wrapped/src/tsc.ts#L70

[adidahiya]

Update: I changed this PR to compile tslint with TS 1.8. This should fix the master branch. I tested the compiled linter with a peer of TS 2.0.3 and it still works.

[alexeagle]

thanks!

[alexeagle]

spelling

[jkillian]

Just so I understand, getDirectories is required by the TS 2.0 typings, but not really required at runtime, so TS 2.0 is fine as a peer? (And a similar story with fileExists?)

[alexeagle]

What is the timeline for compiling tslint with TS 2.0?
Internally we use a single TS version for all compilation, which means I can't sync unmodified tslint into our third party libraries anymore.

[adidahiya]

@alexeagle I just released v4.0.0-dev.0, #1596 (unfortunately it includes some of the v4 breaking changes) -- would that work for your build?

[alexeagle]

I still need the local modification to uncomment lines prefixed with "include this field when compiling with TS 2.0" but it's not a big deal.

[adidahiya]

that release comes from the next branch, which does compile with 2.0, so it includes the new compiler host options: https://github.com/palantir/tslint/blob/next/src/language/utils.ts#L32