feat: 🎸 Add condition detector support

Add condition detector support - added functions: `conditionDetector`,
`mapState`, `mapNextState`, `mapPrevState`, `changed`, `changedFrom`, `changedFromFalsy`,
`changedFromTruthy`, `changedTo`, `changedToFalsy`, `changedToTruthy`, `composeAnd`,
`composeOr`, `mapFalsy`, `mapTruthy`.

BREAKING CHANGE: 🧨 Renamed function `rmountDetector` to `mapState`.

Author: Piotr Oleś

.travis.yml

@@ -12,9 +12,16 @@ script:
   - yarn test --ci
 
 deploy:
-  provider: script
-  skip_cleanup: true
-  script:
-    - yarn exec semantic-release
-  on:
-    branch: master
+  - provider: script
+    skip_cleanup: true
+    script:
+      - yarn exec semantic-release
+    on:
+      branch: develop
+
+  - provider: script
+    skip_cleanup: true
+    script:
+      - yarn exec semantic-release
+    on:
+      branch: master

package.json

@@ -70,6 +70,16 @@
       }
     }
   },
+  "release": {
+    "branches": [
+      "master",
+      {
+        "name": "develop",
+        "channel": "beta",
+        "prerelease": "rc"
+      }
+    ]
+  },
   "devDependencies": {
     "@commitlint/config-conventional": "^7.5.0",
     "@types/jest": "^24.0.0",

src/Detector.ts

@@ -4,8 +4,8 @@ import { Action, AnyAction } from "redux";
  * Function that reduces previous and next state to single value.
  */
 export type Detector<TState = any, TResult = any> = (
-  prevState?: TState,
-  nextState?: TState
+  prevState: TState | undefined,
+  nextState: TState | undefined
 ) => TResult;
 
 /**

src/index.ts

@@ -9,4 +9,20 @@ export { createDetectorEnhancer } from "./createDetectorEnhancer";
 // standard library
 export { composeDetectors } from "./lib/composeDetectors";
 export { combineDetectors } from "./lib/combineDetectors";
-export { mountDetector } from "./lib/mountDetector";
+export { conditionDetector } from "./lib/conditionDetector";
+export { mapState } from "./lib/mapState";
+export { mapNextState } from "./lib/mapNextState";
+export { mapPrevState } from "./lib/mapPrevState";
+export { composeAnd } from "./lib/composeAnd";
+export { composeOr } from "./lib/composeOr";
+export { mapFalsy } from "./lib/mapFalsy";
+export { mapTruthy } from "./lib/mapTruthy";
+
+// standard library changed detectors
+export { changed } from "./lib/changed/changed";
+export { changedFrom } from "./lib/changed/changedFrom";
+export { changedFromFalsy } from "./lib/changed/changedFromFalsy";
+export { changedFromTruthy } from "./lib/changed/changedFromTruthy";
+export { changedTo } from "./lib/changed/changedTo";
+export { changedToFalsy } from "./lib/changed/changedToFalsy";
+export { changedToTruthy } from "./lib/changed/changedToTruthy";

src/lib/changed/changed.ts

@@ -0,0 +1,9 @@
+/**
+ * Condition detector that checks if state changed somehow using shallow equal compare
+ */
+export function changed<TState>(
+  prevState?: TState,
+  nextState?: TState
+): boolean {
+  return prevState !== nextState;
+}

src/lib/changed/changedFrom.ts

@@ -0,0 +1,12 @@
+import { ConditionDetector } from "../../Detector";
+
+/**
+ * Condition detector that checks if state changed somehow and previous step was equal expected state.
+ */
+export function changedFrom<TState>(
+  expectedPrevState: TState
+): ConditionDetector<TState> {
+  return function changedFromDetector(prevState, nextState) {
+    return prevState !== nextState && prevState === expectedPrevState;
+  };
+}

src/lib/changed/changedFromFalsy.ts

@@ -0,0 +1,9 @@
+/**
+ * Condition detector that checks if state changed somehow and previous state was falsy
+ */
+export function changedFromFalsy<TState>(
+  prevState?: TState,
+  nextState?: TState
+): boolean {
+  return prevState !== nextState && !prevState;
+}

src/lib/changed/changedFromTruthy.ts

@@ -0,0 +1,9 @@
+/**
+ * Condition detector that checks if state changed somehow and previous state was truthy
+ */
+export function changedFromTruthy<TState>(
+  prevState?: TState,
+  nextState?: TState
+): boolean {
+  return prevState !== nextState && !!prevState;
+}

src/lib/changed/changedTo.ts

@@ -0,0 +1,12 @@
+import { ConditionDetector } from "../../Detector";
+
+/**
+ * Condition detector that checks if state changed somehow and next step was equal expected state.
+ */
+export function changedTo<TState>(
+  expectedNextState: TState
+): ConditionDetector<TState> {
+  return function changedFromDetector(prevState, nextState) {
+    return prevState !== nextState && nextState === expectedNextState;
+  };
+}

src/lib/changed/changedToFalsy.ts

@@ -0,0 +1,9 @@
+/**
+ * Condition detector that checks if state changed somehow and next state is falsy
+ */
+export function changedToFalsy<TState>(
+  prevState?: TState,
+  nextState?: TState
+): boolean {
+  return prevState !== nextState && !nextState;
+}