Initial prototype fix for issue #2651 (#2652)

* Initial prototype fix

* Add implementation/test for async

* Fix formatting

deno/lib/__tests__/function.test.ts

@@ -29,6 +29,32 @@ test("function inference 1", () => {
   util.assertEqual<func1, (k: string) => number>(true);
 });
 
+test("method parsing", () => {
+  const methodObject = z.object({
+    property: z.number(),
+    method: z.function().args(z.string()).returns(z.number())
+  });
+  const methodInstance = {
+    property: 3,
+    method: function(s: string) { return s.length + this.property; }
+  };
+  const parsed = methodObject.parse(methodInstance);
+  expect(parsed.method('length=8')).toBe(11); // 8 length + 3 property
+});
+
+test("async method parsing", async () => {
+  const methodObject = z.object({
+    property: z.number(),
+    method: z.function().args(z.string()).returns(z.promise(z.number()))
+  });
+  const methodInstance = {
+    property: 3,
+    method: async function(s: string) { return s.length + this.property; }
+  };
+  const parsed = methodObject.parse(methodInstance);
+  expect(await parsed.method('length=8')).toBe(11); // 8 length + 3 property
+});
+
 test("args method", () => {
   const t1 = z.function();
   type t1 = z.infer<typeof t1>;

deno/lib/types.ts

@@ -3736,17 +3736,21 @@ export class ZodFunction<
     const fn = ctx.data;
 
     if (this._def.returns instanceof ZodPromise) {
-      return OK(async (...args: any[]) => {
+      // Would love a way to avoid disabling this rule, but we need
+      // an alias (using an arrow function was what caused 2651).
+      // eslint-disable-next-line @typescript-eslint/no-this-alias
+      const me = this;
+      return OK(async function (this: any, ...args: any[]) {
         const error = new ZodError([]);
-        const parsedArgs = await this._def.args
+        const parsedArgs = await me._def.args
           .parseAsync(args, params)
           .catch((e) => {
             error.addIssue(makeArgsIssue(args, e));
             throw error;
           });
-        const result = await fn(...(parsedArgs as any));
+        const result = await Reflect.apply(fn, this, parsedArgs as any);
         const parsedReturns = await (
-          this._def.returns as unknown as ZodPromise<ZodTypeAny>
+          me._def.returns as unknown as ZodPromise<ZodTypeAny>
         )._def.type
           .parseAsync(result, params)
           .catch((e) => {
@@ -3756,13 +3760,17 @@ export class ZodFunction<
         return parsedReturns;
       });
     } else {
-      return OK((...args: any[]) => {
-        const parsedArgs = this._def.args.safeParse(args, params);
+      // Would love a way to avoid disabling this rule, but we need
+      // an alias (using an arrow function was what caused 2651).
+      // eslint-disable-next-line @typescript-eslint/no-this-alias
+      const me = this;
+      return OK(function (this: any, ...args: any[]) {
+        const parsedArgs = me._def.args.safeParse(args, params);
         if (!parsedArgs.success) {
           throw new ZodError([makeArgsIssue(args, parsedArgs.error)]);
         }
-        const result = fn(...(parsedArgs.data as any));
-        const parsedReturns = this._def.returns.safeParse(result, params);
+        const result = Reflect.apply(fn, this, parsedArgs.data);
+        const parsedReturns = me._def.returns.safeParse(result, params);
         if (!parsedReturns.success) {
           throw new ZodError([makeReturnsIssue(result, parsedReturns.error)]);
         }

src/__tests__/function.test.ts

@@ -28,6 +28,32 @@ test("function inference 1", () => {
   util.assertEqual<func1, (k: string) => number>(true);
 });
 
+test("method parsing", () => {
+  const methodObject = z.object({
+    property: z.number(),
+    method: z.function().args(z.string()).returns(z.number())
+  });
+  const methodInstance = {
+    property: 3,
+    method: function(s: string) { return s.length + this.property; }
+  };
+  const parsed = methodObject.parse(methodInstance);
+  expect(parsed.method('length=8')).toBe(11); // 8 length + 3 property
+});
+
+test("async method parsing", async () => {
+  const methodObject = z.object({
+    property: z.number(),
+    method: z.function().args(z.string()).returns(z.promise(z.number()))
+  });
+  const methodInstance = {
+    property: 3,
+    method: async function(s: string) { return s.length + this.property; }
+  };
+  const parsed = methodObject.parse(methodInstance);
+  expect(await parsed.method('length=8')).toBe(11); // 8 length + 3 property
+});
+
 test("args method", () => {
   const t1 = z.function();
   type t1 = z.infer<typeof t1>;

src/types.ts

@@ -3736,17 +3736,21 @@ export class ZodFunction<
     const fn = ctx.data;
 
     if (this._def.returns instanceof ZodPromise) {
-      return OK(async (...args: any[]) => {
+      // Would love a way to avoid disabling this rule, but we need
+      // an alias (using an arrow function was what caused 2651).
+      // eslint-disable-next-line @typescript-eslint/no-this-alias
+      const me = this;
+      return OK(async function (this: any, ...args: any[]) {
         const error = new ZodError([]);
-        const parsedArgs = await this._def.args
+        const parsedArgs = await me._def.args
           .parseAsync(args, params)
           .catch((e) => {
             error.addIssue(makeArgsIssue(args, e));
             throw error;
           });
-        const result = await fn(...(parsedArgs as any));
+        const result = await Reflect.apply(fn, this, parsedArgs as any);
         const parsedReturns = await (
-          this._def.returns as unknown as ZodPromise<ZodTypeAny>
+          me._def.returns as unknown as ZodPromise<ZodTypeAny>
         )._def.type
           .parseAsync(result, params)
           .catch((e) => {
@@ -3756,13 +3760,17 @@ export class ZodFunction<
         return parsedReturns;
       });
     } else {
-      return OK((...args: any[]) => {
-        const parsedArgs = this._def.args.safeParse(args, params);
+      // Would love a way to avoid disabling this rule, but we need
+      // an alias (using an arrow function was what caused 2651).
+      // eslint-disable-next-line @typescript-eslint/no-this-alias
+      const me = this;
+      return OK(function (this: any, ...args: any[]) {
+        const parsedArgs = me._def.args.safeParse(args, params);
         if (!parsedArgs.success) {
           throw new ZodError([makeArgsIssue(args, parsedArgs.error)]);
         }
-        const result = fn(...(parsedArgs.data as any));
-        const parsedReturns = this._def.returns.safeParse(result, params);
+        const result = Reflect.apply(fn, this, parsedArgs.data);
+        const parsedReturns = me._def.returns.safeParse(result, params);
         if (!parsedReturns.success) {
           throw new ZodError([makeReturnsIssue(result, parsedReturns.error)]);
         }