feat(match): allow to pass a checker instead of a predicate

gvergnaud · Aug 1, 2023 · ac50c84 · ac50c84
1 parent 82e8dc1
commit ac50c84
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diff --git a/src/internals/match/Match.ts b/src/internals/match/Match.ts
@@ -47,4 +47,5 @@ export namespace Match {
   export type With<pattern, handler> = Impl.With<pattern, handler, PatternMatchFn>;
   export type WithExact<pattern, handler> = Impl.With<pattern, handler, ExactMatchFn>;
   export type WithPredicate<predicate extends Fn, pattern, handler> = Impl.With<pattern, handler, predicate>;
+  export type WithChecker<checker extends Fn, handler> = Impl.With<never, handler, checker>;
 }
diff --git a/test/match.test.ts b/test/match.test.ts
@@ -13,6 +13,7 @@ import {
   arg1,
   ComposeLeft,
   Constant,
+  Fn,
   Pipe,
 } from "../src/internals/core/Core";
 import { Equal, Expect } from "../src/internals/helpers";
@@ -138,8 +139,97 @@ describe("Match", () => {
     type res4 = MatchTest<{ msg: "hello" }>;
     //    ^?
     type test4 = Expect<Equal<res4, "don't match strictly with the provided types">>;
+  });
+
+  it("should match with predicates", () => {
 
+    interface TestPredicate extends Fn {
+      return: this["arg0"] extends this["arg1"] ? true : false;
+    }
+
+    type MatchTest<T> = Call<
+      Match<
+        T,
+        [
+          Match.WithPredicate<TestPredicate, string, Constant<"string">>,
+          Match.WithPredicate<TestPredicate, number, Constant<"number">>,
+          Match.WithPredicate<TestPredicate, boolean, Constant<"boolean">>,
+        ]
+      >
+    >;
+
+    type res1 = MatchTest<"hello">;
+    //    ^?
+    type test1 = Expect<Equal<res1, "string">>;
+
+    type res2 = MatchTest<string>;
+    //    ^?
+    type test2 = Expect<Equal<res2, "string">>;
+
+    type res3 = MatchTest<1>;
+    //    ^?
+    type test3 = Expect<Equal<res3, "number">>;
+
+    type res4 = MatchTest<number>;
+    //    ^?
+    type test4 = Expect<Equal<res4, "number">>;
+
+    type res5 = MatchTest<true>;
+    //    ^?
+    type test5 = Expect<Equal<res5, "boolean">>;
+
+    type res6 = MatchTest<boolean>;
+    //    ^?
+    type test6 = Expect<Equal<res6, "boolean">>;
+  });
 
+  it("should match with checker", () => {
+    interface TestStringChecker extends Fn {
+      return: this["arg0"] extends string ? true : false;
+    }
+
+    interface TestNumberChecker extends Fn {
+      return: this["arg0"] extends number ? true : false;
+    }
+
+    interface TestBooleanChecker extends Fn {
+      return: this["arg0"] extends boolean ? true : false;
+    }
+
+    type MatchTest<T> = Call<
+      Match<
+        T,
+        [
+          Match.WithChecker<TestStringChecker, Constant<"string">>,
+          Match.WithChecker<TestNumberChecker, Constant<"number">>,
+          Match.WithChecker<TestBooleanChecker, Constant<"boolean">>,
+        ]
+      >
+    >;
+
+    type res1 = MatchTest<"hello">;
+    //    ^?
+    type test1 = Expect<Equal<res1, "string">>;
+
+    type res2 = MatchTest<string>;
+    //    ^?
+    type test2 = Expect<Equal<res2, "string">>;
+
+    type res3 = MatchTest<1>;
+    //    ^?
+    type test3 = Expect<Equal<res3, "number">>;
+
+    type res4 = MatchTest<number>;
+    //    ^?
+    type test4 = Expect<Equal<res4, "number">>;
+
+    type res5 = MatchTest<true>;
+    //    ^?
+    type test5 = Expect<Equal<res5, "boolean">>;
+
+    type res6 = MatchTest<boolean>;
+    //    ^?
+    type test6 = Expect<Equal<res6, "boolean">>;
   });
 
   it("Handlers can also be regular values", () => {