Preparation for typescript 2.4

[kwoon]

Typescript Changes

Please read about Week Types.

[coveralls]

Coverage remained the same at 100.0% when pulling bb496c8 on kwoon:preparation-for-typescript-2.4 into d213b08 on developit:master.

[jamesbirtles]

I feel like this further supports #620

[marvinhagemeister]

This PR fixes an issue we just stumbled upon at work:

48  abstract class Component<PropsType, StateType> implements ComponentLifecycle<PropsType, StateType> {
                   ~~~~~~~~~

node_modules/preact/dist/preact.d.ts(48,17): error TS2559: Type 'Component<PropsType, StateType>' has no properties in common with type 'ComponentLifecycle<PropsType, StateType>

+1 on merging this PR

[marvinhagemeister]

@developit Any chance this might get merged? This makes preact work again with the latest TypeScript version.

[disintegrator]

Great stuff! I also wanted a fix for the TS 2.4 compile error. While this does overcome the weak type overlap compile error, it does result in an unnecessary abstract class. ComponentLifecycle<P,S> isn't really an appropriate abstract class to expose to consumers as part of the public API. Furthermore, it is not referred to or extended by any type other than Component<P,S>. Perhaps, the more appropriate solution is to place all the lifecycle methods under Component<P,S> and then deleting ComponentLifecycle<P,S>. What do y'all think?

[marvinhagemeister]

That sounds great as well! The ComponentLifeCycle interface only has one implementation anyway.

[AdamMaras]

No new TypeScript language features are used in this PR. LGTM 👍

[valotas]

Not directly related, but shouldn't the props be of type PropsType & ComponentProps<this> for the ComponentLifecycle methods?