Improve generic naming

src/index.d.ts

@@ -1,4 +1,4 @@
-export interface FluxStandardAction<T, M> {
+export interface FluxStandardAction<Payload, Meta> {
   /**
    * The `type` of an action identifies to the consumer the nature of the action that has occurred.
    * Two actions with the same `type` MUST be strictly equivalent (using `===`)
@@ -11,7 +11,7 @@ export interface FluxStandardAction<T, M> {
    * By convention, if `error` is `true`, the `payload` SHOULD be an error object.
    * This is akin to rejecting a promise with an error object.
    */
-  payload?: T;
+  payload?: Payload;
   /**
    * The optional `error` property MAY be set to true if the action represents an error.
    * An action whose `error` is true is analogous to a rejected Promise.
@@ -23,24 +23,24 @@ export interface FluxStandardAction<T, M> {
    * The optional `meta` property MAY be any type of value.
    * It is intended for any extra information that is not part of the payload.
    */
-  meta?: M
+  meta?: Meta
 }
 
-export interface ErrorFluxStandardAction<E extends Error, M> extends FluxStandardAction<E, M> {
+export interface ErrorFluxStandardAction<CustomError extends Error, Meta> extends FluxStandardAction<CustomError, Meta> {
   error: true
 }
 
 /**
  * Alias to FluxStandardAction for shorthand
  */
-export type FSA<T, M> = FluxStandardAction<T, M>;
+export type FSA<Payload, Meta> = FluxStandardAction<Payload, Meta>;
 
 /**
  * Returns `true` if `action` is FSA compliant.
  */
-export function isFSA<P, M>(action: any): action is FluxStandardAction<P, M>;
+export function isFSA<Payload, Meta>(action: any): action is FluxStandardAction<Payload, Meta>;
 
 /**
  * Returns `true` if `action` is FSA compliant error.
  */
-export function isError<E extends Error>(action: any): action is ErrorFluxStandardAction<E, any>;
+export function isError<CustomError extends Error, Meta>(action: any): action is ErrorFluxStandardAction<CustomError, Meta>;

test/typings-test.ts

@@ -46,7 +46,7 @@ function reducer(state, action) {
     let iserr: true = action.error // iserr === true
     let err: Error = action.payload
   }
-  else if (isError<MyError>(action)) {
+  else if (isError<MyError, void>(action)) {
     let err: MyError = action.payload
   }
 }