feat: add ofType operator

closes #11

package.json

@@ -27,6 +27,7 @@
     "clean": "rimraf tmp dist coverage"
   },
   "dependencies": {
+    "rxjs": "^6.3.3",
     "tslib": "^1.9.3"
   },
   "devDependencies": {
@@ -53,6 +54,7 @@
     "rollup-plugin-sizes": "^0.4.2",
     "rollup-plugin-sourcemaps": "^0.4.2",
     "rollup-plugin-terser": "^4.0.2",
+    "rxjs-marbles": "^5.0.0",
     "semantic-release": "^15.13.3",
     "ts-jest": "^23.10.5",
     "tslint": "^5.12.1",

src/__tests__/__snapshots__/index.spec.ts.snap

@@ -6,5 +6,6 @@ Object {
   "createAction": [Function],
   "createReducer": [Function],
   "getType": [Function],
+  "ofType": [Function],
 }
 `;

src/__tests__/__snapshots__/of-type.dts.spec.ts.snap

@@ -0,0 +1,13 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`ofType of(a(), b(), c()).pipe(ofType('a')) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType('a')) 1`] = `"Observable<{ type: \\"a\\"; } | { type: \\"b\\"; } | { type: \\"c\\"; }>"`;
+
+exports[`ofType of(a(), b(), c()).pipe(ofType(['a', 'b'])) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType(['a', 'b'])) 1`] = `"Observable<{ type: \\"a\\"; } | { type: \\"b\\"; } | { type: \\"c\\"; }>"`;
+
+exports[`ofType of(a(), b(), c()).pipe(ofType([a(), b()])) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType([a(), b()])) 1`] = `"Observable<{ type: \\"a\\"; } | { type: \\"b\\"; }>"`;
+
+exports[`ofType of(a(), b(), c()).pipe(ofType([a, b])) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType([a, b])) 1`] = `"Observable<{ type: \\"a\\"; } | { type: \\"b\\"; }>"`;
+
+exports[`ofType of(a(), b(), c()).pipe(ofType(a())) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType(a())) 1`] = `"Observable<{ type: \\"a\\"; }>"`;
+
+exports[`ofType of(a(), b(), c()).pipe(ofType(a)) (type) should match snapshot: ofType of(a(), b(), c()).pipe(ofType(a)) 1`] = `"Observable<{ type: \\"a\\"; }>"`;

src/__tests__/of-type.dts.spec.ts

@@ -0,0 +1,28 @@
+import { of } from 'rxjs'
+
+import { createAction } from '../create-action'
+import { ofType } from '../of-type'
+
+// @dts-jest:group ofType
+
+const a = createAction('a')
+const b = createAction('b')
+const c = createAction('c')
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType(a))
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType([a, b]))
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType(a()))
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType([a(), b()]))
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType('a'))
+
+// @dts-jest:pass:snap
+of(a(), b(), c()).pipe(ofType(['a', 'b']))

src/__tests__/of-type.spec.ts

@@ -0,0 +1,80 @@
+import { marbles } from 'rxjs-marbles/jest'
+
+import { createAction } from '../create-action'
+import { ofType } from '../of-type'
+
+describe('ofType', () => {
+  const a = createAction('a')
+  const b = createAction('b')
+  const c = createAction('c')
+  const d = createAction('d')
+  const e = createAction('e')
+  const f = createAction('f')
+  const g = createAction('g')
+  const h = createAction('h')
+
+  const values = {
+    a: a(),
+    b: b(),
+    c: c(),
+    d: d(),
+    e: e(),
+    f: f(),
+    g: g(),
+    h: h(),
+  }
+
+  const test = ({ action, subs, expected, keys }: any) =>
+    marbles(m => {
+      const action$ = m.hot(action, values)
+      const expected$ = m.cold(expected, values)
+
+      m.expect(action$.pipe(ofType(keys))).toBeObservable(expected$)
+      m.expect(action$).toHaveSubscriptions(subs)
+    })()
+
+  it.each([
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c-----------c-----|',
+      keys: c,
+    },
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c--d-----f--c-----|',
+      keys: [c, d, f],
+    },
+  ])('should filter in with action creator(s)', test)
+
+  it.each([
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c-----------c-----|',
+      keys: c(),
+    },
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c--d-----f--c-----|',
+      keys: [c(), d(), f()],
+    },
+  ])('should filter in with action(s)', test)
+
+  it.each([
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c-----------c-----|',
+      keys: 'c',
+    },
+    {
+      action: '  -a--b-^-c--d--e--f--c--h--|',
+      subs: '          ^-------------------!',
+      expected: '      --c--d-----f--c-----|',
+      keys: ['c', 'd', 'f'],
+    },
+  ])('should filter in with action type(s)', test)
+})

src/index.ts

@@ -2,3 +2,4 @@ export { action, Action, AnyAction } from './action'
 export { createAction, ActionCreator } from './create-action'
 export { getType } from './get-type'
 export { createReducer } from './create-reducer'
+export { ofType } from './of-type'

src/of-type.ts

@@ -0,0 +1,36 @@
+import { filter } from 'rxjs/operators'
+
+import { ActionCreator } from './create-action'
+import { AnyAction } from './action'
+import { getType } from './get-type'
+
+/**
+ * Filter actions emitted by the source Observable by only emitting those that
+ * are compatible with specified action(s) or action creator(s) or action type(s).
+ *
+ * @example
+ * action$.pipe(
+ *   ofType(foo),
+ *   ...
+ * )
+ * @example
+ * action$.pipe(
+ *   ofType([foo, bar]),
+ *   ...
+ * )
+ */
+export function ofType<
+  Source extends AnyAction,
+  Key extends ActionCreator<Source> | Source | Source['type'],
+  Sink extends Source = Key extends (...args: any[]) => infer U
+    ? (U extends Source ? U : never)
+    : (Key extends Source ? Key : never)
+>(keys: Key | Key[]) {
+  const types: string[] = (Array.isArray(keys) ? keys : [keys]).map(key =>
+    typeof key === 'string' ? key : getType(key)
+  )
+
+  return filter<Source, Sink>(
+    (action): action is Sink => types.includes(action.type)
+  )
+}

yarn.lock

@@ -2265,6 +2265,11 @@ fast-deep-equal@^2.0.1:
   resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-2.0.1.tgz#7b05218ddf9667bf7f370bf7fdb2cb15fdd0aa49"
   integrity sha1-ewUhjd+WZ79/Nwv3/bLLFf3Qqkk=
 
+fast-equals@^1.6.1:
+  version "1.6.2"
+  resolved "https://registry.yarnpkg.com/fast-equals/-/fast-equals-1.6.2.tgz#f1762bde0d571b5e9d4e1c4ae0599792f6a6df5f"
+  integrity sha512-6FiKwHkrHIqdvo9I92yzCR/zuWE6iy5ldcOszStPbmo7Zzj3OoVeng++GE//JqO4i6JQ4vH/BVAfCmUCki+C3g==
+
 fast-glob@^2.2.6:
   version "2.2.6"
   resolved "https://registry.yarnpkg.com/fast-glob/-/fast-glob-2.2.6.tgz#a5d5b697ec8deda468d85a74035290a025a95295"
@@ -6672,6 +6677,13 @@ run-queue@^1.0.0, run-queue@^1.0.3:
   dependencies:
     aproba "^1.1.1"
 
+rxjs-marbles@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/rxjs-marbles/-/rxjs-marbles-5.0.0.tgz#b46b4d6ed8ff62da9b5da6df1bcb423df56c72f4"
+  integrity sha512-Twr69tKSxC4ObE/afKJtSPuw+hVE5Paul8KlHhVsnOpqnSHiOd9Ff94RUx+fsCXYsnEILrf4qLsXpHlYzG4a9Q==
+  dependencies:
+    fast-equals "^1.6.1"
+
 rxjs@^6.3.3:
   version "6.3.3"
   resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.3.3.tgz#3c6a7fa420e844a81390fb1158a9ec614f4bad55"