Merge pull request #5 from Raini-js/dev

v1.1.0

Author: Sergei Orlov

.gitignore

@@ -9,3 +9,4 @@ tsconfig.tsbuildinfo
 *.d.ts
 *.map
 *.js
+!jest.config.js

index.ts

@@ -1,5 +1,6 @@
 import { TNonFunction, TPredicateFunction } from "./TPredicateFunction";
 import { TKnown } from "./TKnown";
+import { Unpack } from "./Switch";
 
 /**
  * ISwitch for cases when K is defined.
@@ -14,16 +15,16 @@ export interface ISwitch<T, K> {
   /**
    * Define predicate to be matched against and the value to be returned in case of matching.
    */
-  case<N>(pred: TNonFunction<T>, value: TKnown<K, N>): TDefinedSwitch<T, K, N>;
+  case<N>(pred: TNonFunction<T>, value: N): ISwitch<T, [Unpack<K>, N]>;
 
   /**
    * Define predicate function to be executed against Switch state and the value to be
    * returned in case of matching.
    */
-  case<N>(pred: TPredicateFunction<T>, value: TKnown<K, N>): TDefinedSwitch<T, K, N>;
+  case<N>(pred: TPredicateFunction<T>, value: N): ISwitch<T, [Unpack<K>, N]>;
 
   /**
    * Define the value to be returned in case none of the cases was matched.
    */
-  default<N>(defaultValue: N): K | N;
+  default<N>(defaultValue: N): Unpack<K> | N;
 }

src/ISwitch.ts

@@ -1,6 +1,7 @@
 import { TNonFunction, TPredicateFunction } from "./TPredicateFunction";
-import { ISwitch, TDefinedSwitch } from "./ISwitch";
-import { TKnown } from "./TKnown";
+import { ISwitch } from "./ISwitch";
+
+export type Unpack<T> = T extends (infer U)[] ? U : T;
 
 class SwitchMatched<T, K> implements ISwitch<T, K> {
   public static for<T>(x: T): any {
@@ -26,11 +27,11 @@ class SwitchMatched<T, K> implements ISwitch<T, K> {
  * Switch becomes a kind of Left and holds the value until it reaches the .default call. If
  * matching didn't happen for all cases, the value of the .default argument is returned instead.
  */
-export class Switch<T, K> implements ISwitch<T, K> {
+export class Switch<T, K extends any[]> implements ISwitch<T, K> {
   /**
    * Pointer interface for lifting a value into Switch.
    */
-  public static for<T, K>(x: T): ISwitch<T, K> {
+  public static for<T, K extends any[] = []>(x: T): ISwitch<T, K> {
     return new Switch<T, K>(x);
   }
 
@@ -42,14 +43,14 @@ export class Switch<T, K> implements ISwitch<T, K> {
   /**
    * Define predicate to be matched against and the value to be returned in case of matching.
    */
-  public case<N>(pred: TNonFunction<T>, value: TKnown<K, N>): TDefinedSwitch<T, K, N>;
+  public case<N>(pred: TNonFunction<T>, value: N): ISwitch<T, [Unpack<K>, N]>;
 
   /**
    * Define predicate function to be executed against Switch state and the value to be
    * returned in case of matching.
    */
-  public case<N>(pred: TPredicateFunction<T>, res: TKnown<K, N>): TDefinedSwitch<T, K, N>;
-  public case<N>(pred: any, res: TKnown<K, N>): TDefinedSwitch<T, K, N> {
+  public case<N>(pred: TPredicateFunction<T>, res: N): ISwitch<T, [Unpack<K>, N]>;
+  public case<N>(pred: any, res: N): ISwitch<T, [Unpack<K>, N]> {
     const check = typeof pred == "function" ? pred(this.x) : pred === this.x;
 
     return check ? SwitchMatched.for(res) : Switch.for(this.x);
@@ -58,7 +59,7 @@ export class Switch<T, K> implements ISwitch<T, K> {
   /**
    * Define the value to be returned in case none of the cases was matched.
    */
-  public default<V>(defaultValue: V): K | V {
+  public default<V>(defaultValue: V): Unpack<K> | V {
     return defaultValue;
   }
 }

src/Switch.ts

@@ -1,7 +1,4 @@
-type TIsKnown<X, Y> = X extends unknown ? Y : X;
-
 /**
  * Returns the second type if the first type extends unknown.
- * @type TIsKnown
  */
-export type TKnown<T, K> = T extends TIsKnown<T, K> ? T : K;
+export type TKnown<T, K> = never extends T ? K : T;

src/TKnown.ts

@@ -1,4 +1,13 @@
+import { Switch } from "./Switch";
+
 export * from "./ISwitch";
 export * from "./Switch";
 export * from "./TKnown";
 export * from "./TPredicateFunction";
+
+/**
+ * Pointer interface for lifting value provided as an argument to Switch.
+ */
+export default function<T, K extends any[]>(x: T) {
+  return Switch.for<T, K>(x);
+}

src/index.ts

@@ -1,5 +1,5 @@
 import { Switch } from "../src";
-import match from "../";
+import match from "../src";
 
 describe("Switch", () => {
   it("should exist", () => {

tests/Switch.spec.ts

@@ -4,9 +4,10 @@
     "target": "es6" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */,
     "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
     "lib": ["es2018"] /* Specify library files to be included in the compilation. */,
+    "baseUrl": "./src",
     "sourceMap": true,
     "declaration": true,
-
+    "outDir": "./",
     /* Strict Type-Checking Options */
     "strict": true /* Enable all strict type-checking options. */,
     "noImplicitAny": true /* Raise error on expressions and declarations with an implied 'any' type. */,
@@ -34,5 +35,9 @@
 
     /* Advanced Options */
     "forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */
-  }
+  },
+  "exclude": [
+    "node_modules",
+    "tests"
+  ]
 }