feat(effects): add createEffect function (#1667)

Closes #1368

Author: timdeschryver

modules/effects/spec/create_effect.spec.ts

@@ -0,0 +1,61 @@
+import { of } from 'rxjs';
+import { createEffect, getCreateEffectMetadata } from '../src/effect_creator';
+
+describe('createEffect()', () => {
+  it('should flag the variable with a meta tag', () => {
+    const effect = createEffect(() => of({ type: 'a' }));
+
+    expect(effect.hasOwnProperty('__@ngrx/effects_create__')).toBe(true);
+  });
+
+  it('should dispatch by default', () => {
+    const effect: any = createEffect(() => of({ type: 'a' }));
+
+    expect(effect['__@ngrx/effects_create__']).toEqual({ dispatch: true });
+  });
+
+  it('should be possible to explicitly create a dispatching effect', () => {
+    const effect: any = createEffect(() => of({ type: 'a' }), {
+      dispatch: true,
+    });
+
+    expect(effect['__@ngrx/effects_create__']).toEqual({ dispatch: true });
+  });
+
+  it('should be possible to create a non-dispatching effect', () => {
+    const effect: any = createEffect(() => of({ type: 'a' }), {
+      dispatch: false,
+    });
+
+    expect(effect['__@ngrx/effects_create__']).toEqual({ dispatch: false });
+  });
+
+  describe('getCreateEffectMetadata', () => {
+    it('should get the effects metadata for a class instance', () => {
+      class Fixture {
+        a = createEffect(() => of({ type: 'a' }));
+        b = createEffect(() => of({ type: 'b' }), { dispatch: true });
+        c = createEffect(() => of({ type: 'c' }), { dispatch: false });
+      }
+
+      const mock = new Fixture();
+
+      expect(getCreateEffectMetadata(mock)).toEqual([
+        { propertyName: 'a', dispatch: true },
+        { propertyName: 'b', dispatch: true },
+        { propertyName: 'c', dispatch: false },
+      ]);
+    });
+
+    it('should return an empty array if the effect has not been created with createEffect()', () => {
+      const fakeCreateEffect: any = () => {};
+      class Fixture {
+        a = fakeCreateEffect(() => of({ type: 'A' }));
+      }
+
+      const mock = new Fixture();
+
+      expect(getCreateEffectMetadata(mock)).toEqual([]);
+    });
+  });
+});

modules/effects/spec/effect_decorator.spec.ts

@@ -0,0 +1,32 @@
+import { Effect, getEffectDecoratorMetadata } from '../src/effect_decorator';
+
+describe('@Effect()', () => {
+  describe('getEffectDecoratorMetadata', () => {
+    it('should get the effects metadata for a class instance', () => {
+      class Fixture {
+        @Effect() a: any;
+        @Effect() b: any;
+        @Effect({ dispatch: false })
+        c: any;
+      }
+
+      const mock = new Fixture();
+
+      expect(getEffectDecoratorMetadata(mock)).toEqual([
+        { propertyName: 'a', dispatch: true },
+        { propertyName: 'b', dispatch: true },
+        { propertyName: 'c', dispatch: false },
+      ]);
+    });
+
+    it('should return an empty array if the class has not been decorated', () => {
+      class Fixture {
+        a: any;
+      }
+
+      const mock = new Fixture();
+
+      expect(getEffectDecoratorMetadata(mock)).toEqual([]);
+    });
+  });
+});