unique symbol type for Cmd.getState, Cmd.dispatch

[laszlopandy]

Typescript 2.7 added unique symbol to describe symbol types which are unique. Otherwise the types of Cmd.getState and Cmd.dispatch are assignable to each other.

[bdwain]

Is this backwards compatible? Does this raise the minimum typescript version? Or are 2.7 features already being used?

[laszlopandy]

These are good questions.
No unique symbol is not backwards compatible. It will cause an syntax exception for anyone using an earlier version of typescript.

I'm not sure if any other syntax being used requires >=2.7. The only way to ensure that would be to downgrade the typescript version in package.json and run the tests. Therefore, I assumed that the minimum version is what is specified in the package.json (typescript 3.2.2). Is a minimum version specified somewhere else?

[laszlopandy]

If it is important to maintain backwards compatibility, it is possible to specify multiple index.d.ts files which will be used by different versions of the typescript compiler:
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-1.html#version-selection-with-typesversions

[laszlopandy]

@bdwain I tested a range of typescript versions and it seems that redux is already using syntax that requires >=2.8. So it is safe to say that unique symbol does not raise the minimum typescript version for redux-loop.

[bdwain]

@laszlopandy great sorry for the delay thanks for looking into that