Add recordOf

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@endeavorance/parsec",
-  "version": "0.6.1",
+  "version": "0.7.0",
   "author": "Endeavorance",
   "type": "module",
   "module": "dist/index.js",

src/index.ts

@@ -261,4 +261,38 @@ export const Parse = {
       throw MismatchError(shapeName, value);
     };
   },
+
+  recordOf<K extends string, V>(
+    keyParser: Parser<K>,
+    valueParser: Parser<V>,
+    shapeName = "Record",
+  ) {
+    return (value: unknown): Record<K, V> => {
+      if (value === null || typeof value !== "object") {
+        throw new ParseError("Record value must be an object", shapeName);
+      }
+
+      for (const [key, val] of Object.entries(value)) {
+        try {
+          keyParser(key);
+        } catch (error) {
+          if (error instanceof ParseError) {
+            error.path += `${shapeName}["${key}"] (key)`;
+          }
+          throw error;
+        }
+
+        try {
+          valueParser(val);
+        } catch (error) {
+          if (error instanceof ParseError) {
+            error.path += `${shapeName}["${key}"] (value)`;
+          }
+          throw error;
+        }
+      }
+
+      return value as Record<K, V>;
+    };
+  },
 } as const;

src/test/parse.test.ts

@@ -319,3 +319,23 @@ describe(Parse.oneOf, () => {
     }
   });
 });
+
+describe(Parse.recordOf, () => {
+  test("Parses records of a specific type", () => {
+    const stringToString = Parse.recordOf(Parse.string, Parse.string);
+
+    const rec = {
+      key: "value",
+      another: "another",
+    };
+
+    const badRec = {
+      key: "value",
+      another: 1,
+    };
+
+    expect(stringToString(rec)).toEqual(rec);
+
+    expect(() => stringToString(badRec)).toThrow(ParseError);
+  });
+});