fix(types): avoid inferring timestamps if methods, virtuals, or `…

…statics` set

Re: #12807

docs/typescript/schemas.md

@@ -64,6 +64,7 @@ There are a few caveats for using automatic type inference:
 
 1. You need to set `strictNullChecks: true` or `strict: true` in your `tsconfig.json`. Or, if you're setting flags at the command line, `--strictNullChecks` or `--strict`. There are [known issues](https://github.com/Automattic/mongoose/issues/12420) with automatic type inference with strict mode disabled.
 2. You need to define your schema in the `new Schema()` call. Don't assign your schema definition to a temporary variable. Doing something like `const schemaDefinition = { name: String }; const schema = new Schema(schemaDefinition);` will not work.
+3. Mongoose adds `createdAt` and `updatedAt` to your schema if you specify the `timestamps` option in your schema, _except_ if you also specify `methods`, `virtuals`, or `statics`. There is a [known issue](https://github.com/Automattic/mongoose/issues/12807) with type inference with timestamps and methods/virtuals/statics options. If you use methods, virtuals, and statics, you're responsible for adding `createdAt` and `updatedAt` to your schema definition.
 
 If automatic type inference doesn't work for you, you can always fall back to document interface definitions.
 

test/types/schema.test.ts

@@ -873,6 +873,22 @@ function testInferTimestamps() {
   // is not identical to argument type { createdAt: NativeDate; updatedAt: NativeDate; } &
   // { name?: string | undefined; }"
   expectType<{ createdAt: Date, updatedAt: Date } & { name?: string }>({} as WithTimestamps);
+
+  const schema2 = new Schema({
+    name: String
+  }, {
+    timestamps: true,
+    methods: { myName(): string | undefined {
+      return this.name;
+    } }
+  });
+
+  type WithTimestamps2 = InferSchemaType<typeof schema2>;
+  // For some reason, expectType<{ createdAt: Date, updatedAt: Date, name?: string }> throws
+  // an error "Parameter type { createdAt: Date; updatedAt: Date; name?: string | undefined; }
+  // is not identical to argument type { createdAt: NativeDate; updatedAt: NativeDate; } &
+  // { name?: string | undefined; }"
+  expectType<{ name?: string }>({} as WithTimestamps2);
 }
 
 function gh12431() {

types/inferschematype.d.ts

@@ -60,12 +60,18 @@ declare module 'mongoose' {
      }[alias]
      : unknown;
 
-  type ResolveSchemaOptions<T> = Omit<MergeType<DefaultSchemaOptions, T>, 'statics' | 'methods' | 'query' | 'virtuals'>;
+  // Without Omit, this gives us a "Type parameter 'TSchemaOptions' has a circular constraint."
+  type ResolveSchemaOptions<T> = Omit<MergeType<DefaultSchemaOptions, T>, 'fakepropertyname'>;
 
   type ApplySchemaOptions<T, O = DefaultSchemaOptions> = ResolveTimestamps<T, O>;
 
   type ResolveTimestamps<T, O> = O extends { timestamps: true }
-    ? { createdAt: NativeDate; updatedAt: NativeDate; } & T
+    // For some reason, TypeScript sets all the document properties to unknown
+    // if we use methods, statics, or virtuals. So avoid inferring timestamps
+    // if any of these are set for now. See gh-12807
+    ? O extends { methods: any } | { statics: any } | { virtuals: any }
+      ? T
+      : { createdAt: NativeDate; updatedAt: NativeDate; } & T
     : T;
 }