Defer to rollup TS plugin to build types

[jednano]

1. No sense in having TS build the types when the TS rollup plugin is already doing it.
2. Renamed index.ts to redux.ts so the types become redux.d.ts; thus, get picked up automatically by editors.

[cellog]

The original PR used es/index.d.ts and this was nuked because there are several directories where source is output (es, lib, and then the browser builds). Can you explain why using lib/ is better than using es or putting into types?

[jednano]

Sure. The Rollup config is already using the TS plugin to dump types into es, lib and dist folders. That means we already have 3 copies of the exact same types. As such, building another types folder just adds a 4th copy, which is even more redundant and unnecessary.

As the types are verbatim the same between es, lib and dist folders, it doesn't entirely matter which redux.d.ts we point to. In fact, you don't technically need to define your types in package.json at all, because it will just look for your main entry for a .d.ts file adjacent to your main filename. If main points to lib/redux.js then it will automatically assume the types are in lib/redux.d.ts. My types entry just reflects that default behavior, which is recommended to do.

Also note that if your main declaration file is named index.d.ts and lives at the root of the package (next to index.js) you do not need to mark the "types" property, though it is advisable to do so.

https://www.typescriptlang.org/docs/handbook/declaration-files/publishing.html#including-declarations-in-your-npm-package

[jednano]

Closing in favor of reduxjs#3564