isActionOf demonstration

index.d.ts

import { ActionType } from "typesafe-actions";
import { ActionsObservable } from "redux-observable";
export declare const actions: {
    toggle: () => {
        type: "todos/TOGGLE";
    };
    add: () => {
        type: "todos/ADD";
    };
    dummy: () => {
        type: "todos/DUMMY";
    };
};
export declare type TestActions = ActionType<typeof actions>;
export declare const epic1: (action$: ActionsObservable<{
    type: "todos/TOGGLE";
} | {
    type: "todos/ADD";
} | {
    type: "todos/DUMMY";
}>) => import("rxjs/internal/Observable").Observable<{
    type: "todos/TOGGLE";
} | {
    type: "todos/ADD";
} | {
    type: "todos/DUMMY";
}>;
export declare const myFilter: (action: {
    type: string;
}) => action is {
    type: string;
} | {
    type: "todos/TOGGLE";
} | {
    type: "todos/ADD";
};
export declare const epic2: (action$: ActionsObservable<{
    type: "todos/TOGGLE";
} | {
    type: "todos/ADD";
} | {
    type: "todos/DUMMY";
}>) => import("rxjs/internal/Observable").Observable<{
    type: string;
} | {
    type: "todos/TOGGLE";
} | {
    type: "todos/ADD";
}>;

index.ts

import { createAction, ActionType, isActionOf } from "typesafe-actions";
import { filter, tap } from "rxjs/operators";
import { ActionsObservable } from "redux-observable";

export const actions = {
  toggle: createAction("todos/TOGGLE"),
  add: createAction("todos/ADD"),
  dummy: createAction("todos/DUMMY")
};

export type TestActions = ActionType<typeof actions>;

export const epic1 = (action$: ActionsObservable<TestActions>) =>
  action$.pipe(
    filter(isActionOf([actions.add, actions.toggle])),
    tap(x => x.type) // x.type:  "todos/TOGGLE" | "todos/ADD" | "todos/DUMMY"
  );

export const myFilter = isActionOf([actions.add, actions.toggle]);

export const epic2 = (action$: ActionsObservable<TestActions>) =>
  action$.pipe(
    filter(myFilter),
    tap(x => x.type) // x.type:  string | "todos/ADD" | "todos/TOGGLE"
  );

package.json

{
  "name": "typescript-test",
  "version": "1.0.0",
  "description": "",
  "main": "test.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
	"start": "tsc -p tsconfig.json --declaration",
	"version": "tsc --version"
  },
  "author": "Christopher Little <christopher@littlehq.uk> (littlesavage.net)",
  "license": "ISC",
  "dependencies": {
    "redux": "^4.0.0",
    "redux-observable": "^1.0.0",
    "rxjs": "^6.2.2",
    "typesafe-actions": "^2.0.4",
    "typescript": "^2.9.2"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "experimentalDecorators": true,
    "forceConsistentCasingInFileNames": true,
    "importHelpers": true,
    "jsx": "react-native",
    "lib": ["es2015", "es2016", "es2017"],
    "types": [],
    "module": "commonjs",
    "moduleResolution": "node",
    "noEmitHelpers": true,
    "noImplicitReturns": true,
    "noUnusedLocals": true,
    "sourceMap": false,
    "strict": true,
    "target": "es6"
  }
}