feat(result): Add onValue and onError handlers (#24099)

renovatebot · Aug 27, 2023 · b2c6cbe · b2c6cbe
1 parent a1c1798
commit b2c6cbe
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Showing 2 changed files with 108 additions and 0 deletions.
diff --git a/lib/util/result.spec.ts b/lib/util/result.spec.ts
@@ -299,6 +299,34 @@ describe('util/result', () => {
         expect(Result.err('oops').parse(schema)).toEqual(Result.err('oops'));
       });
     });
+
+    describe('Handlers', () => {
+      it('supports value handlers', () => {
+        const cb = jest.fn();
+        Result.ok(42).onValue(cb);
+        expect(cb).toHaveBeenCalledWith(42);
+      });
+
+      it('supports error handlers', () => {
+        const cb = jest.fn();
+        Result.err('oops').onError(cb);
+        expect(cb).toHaveBeenCalledWith('oops');
+      });
+
+      it('handles error thrown in value handler', () => {
+        const res = Result.ok(42).onValue(() => {
+          throw 'oops';
+        });
+        expect(res).toEqual(Result._uncaught('oops'));
+      });
+
+      it('handles error thrown in error handler', () => {
+        const res = Result.err('oops').onError(() => {
+          throw 'oops';
+        });
+        expect(res).toEqual(Result._uncaught('oops'));
+      });
+    });
   });
 
   describe('AsyncResult', () => {
@@ -621,4 +649,32 @@ describe('util/result', () => {
       expect(res).toEqual(Result._uncaught('oops'));
     });
   });
+
+  describe('Handlers', () => {
+    it('supports value handlers', async () => {
+      const cb = jest.fn();
+      await AsyncResult.ok(42).onValue(cb);
+      expect(cb).toHaveBeenCalledWith(42);
+    });
+
+    it('supports error handlers', async () => {
+      const cb = jest.fn();
+      await AsyncResult.err('oops').onError(cb);
+      expect(cb).toHaveBeenCalledWith('oops');
+    });
+
+    it('handles error thrown in value handler', async () => {
+      const res = await AsyncResult.ok(42).onValue(() => {
+        throw 'oops';
+      });
+      expect(res).toEqual(Result._uncaught('oops'));
+    });
+
+    it('handles error thrown in error handler', async () => {
+      const res = await AsyncResult.err('oops').onError(() => {
+        throw 'oops';
+      });
+      expect(res).toEqual(Result._uncaught('oops'));
+    });
+  });
 });
diff --git a/lib/util/result.ts b/lib/util/result.ts
@@ -568,6 +568,36 @@ export class Result<T extends Val, E extends Val = Error> {
 
     return Result.err(err);
   }
+
+  /**
+   * Call `fn` on the `val` if the result is ok.
+   */
+  onValue(fn: (value: T) => void): Result<T, E> {
+    if (this.res.ok) {
+      try {
+        fn(this.res.val);
+      } catch (err) {
+        return Result._uncaught(err);
+      }
+    }
+
+    return this;
+  }
+
+  /**
+   * Call `fn` on the `err` if the result is err.
+   */
+  onError(fn: (err: E) => void): Result<T, E> {
+    if (!this.res.ok) {
+      try {
+        fn(this.res.err);
+      } catch (err) {
+        return Result._uncaught(err);
+      }
+    }
+
+    return this;
+  }
 }
 
 /**
@@ -828,4 +858,26 @@ export class AsyncResult<T extends Val, E extends Val>
         )
     );
   }
+
+  onValue(fn: (value: T) => void): AsyncResult<T, E> {
+    return new AsyncResult(
+      this.asyncResult
+        .then((result) => result.onValue(fn))
+        .catch(
+          /* istanbul ignore next: should never happen */
+          (err) => Result._uncaught(err)
+        )
+    );
+  }
+
+  onError(fn: (err: E) => void): AsyncResult<T, E> {
+    return new AsyncResult(
+      this.asyncResult
+        .then((result) => result.onError(fn))
+        .catch(
+          /* istanbul ignore next: should never happen */
+          (err) => Result._uncaught(err)
+        )
+    );
+  }
 }