Why is CreateLogic.Config.Transform.Hook uses optional argument for reject?

[chenxinyanc]

When compiling with tsc and --strict switched on, I found error in createLogic callback. Specifically, tsc indicates reject parameter in transform function can be undefined. I checked the type definition:

redux-logic/definitions/logic.d.ts

Lines 216 to 240 in 4b0951a

	/* ----- transform ----- */
	interface Transform<
	State,
	Action extends ActionBasis,
	Dependency extends object,
	Context extends Object
	> {
	transform?: Transform.Hook<State, Action, Dependency, Context>;
	}
	export namespace Transform {
	export type Hook<
	State,
	Action extends ActionBasis,
	Dependency extends object,
	Context extends Object = undefined
	> = (
	depObj: DepObj<State, Action, Dependency>,
	next: Pass<Action, Context>,
	reject?: Pass<Action, Context>
	) => void;
	}
	// ---------------------------------------- //

It used reject?: Pass<Action, Context> for transform function signature. I wonder, is there any case where transform can be called with reject neglected? I've checked #124 and #125, but still couldn't figure out why there is ? following reject parameter.

[jeffbski]

The reason that reject is optional in the signature is that transform and validate are just aliases for the same method. validate would necessarily need allow/next and reject. The reason for both is simply to better communicate the intent. Reject wouldn't usually be needed in a transform use case, but left as optional to mirror the validate signature.

[chenxinyanc]

The reason that reject is optional in the signature is that transform and validate are just aliases for the same method.

If I've got this correct, transform and validate are actually the same callback.

redux-logic/src/createLogic.js

Lines 175 to 177 in 4b0951a

	if (validate && transform) {
	throw new Error('logic cannot define both the validate and transform hooks they are aliases');
	}

In this case, I think it would be better if you either

• make reject in transform a non-optional parameter, so when I'm implementing the callback, I do not need to write something like

if (reject) {
    reject(action);
}

because there is actually no case where reject is null, but I will need to make tsc happy. However, you may write some @deprecate notice in tsdoc or some runtime warning to tell me do not use transform for rejct.

• just remove reject parameter in .d.ts for transform, so to force me to choose validate callback because it has a non-optional reject parameter

redux-logic/definitions/logic.d.ts

Lines 201 to 212 in 4b0951a

	export namespace Validate {
	export type Hook<
	State,
	Action extends ActionBasis,
	Dependency extends object,
	Context extends Object = undefined
	> = (
	depObj: DepObj<State, Action, Dependency>,
	allow: Pass<Action, Context>,
	reject: Pass<Action, Context>
	) => void;
	}