Add satisfies type assertion for typescript

compiler/crates/relay-compiler/tests/relay_compiler_integration/fixtures/typescript_resolver_type_import.expected

@@ -25,7 +25,7 @@ type User { name: String }
 ==================================== OUTPUT ===================================
 //- __generated__/barFragment.graphql.ts
 /**
- * <auto-generated> SignedSource<<f592d795251b0c88f6e5456bd47a8d10>>
+ * <auto-generated> SignedSource<<0f778584db7b20b3491a3ed42c61cdc1>>
  * @lightSyntaxTransform
  * @nogrep
  */
@@ -37,6 +37,9 @@ type User { name: String }
 import { ReaderFragment } from 'relay-runtime';
 import { FragmentRefs } from "relay-runtime";
 import { foo as userFooResolverType } from "../foo";
+// Type assertion validating that `userFooResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userFooResolverType satisfies () => unknown | null | undefined);
 export type barFragment$data = {
   readonly foo: ReturnType<typeof userFooResolverType> | null | undefined;
   readonly " $fragmentType": "barFragment";

compiler/crates/relay-compiler/tests/relay_compiler_integration/fixtures/typescript_resolver_with_context.expected

@@ -28,7 +28,7 @@ type User { name: String }
 ==================================== OUTPUT ===================================
 //- __generated__/barFragment.graphql.ts
 /**
- * <auto-generated> SignedSource<<5dff27df4f02d14a44779d79d3f98fbb>>
+ * <auto-generated> SignedSource<<7c2c6939d2e5610ed47a154e9cab2dfd>>
  * @lightSyntaxTransform
  * @nogrep
  */
@@ -38,9 +38,15 @@ type User { name: String }
 // @ts-nocheck
 
 import { ReaderFragment } from 'relay-runtime';
-import { FragmentRefs } from "relay-runtime";
+import { LiveState, FragmentRefs } from "relay-runtime";
 import { foo as userFooResolverType } from "../foo";
 import { ITestResolverContextType } from "@test/package";
+// Type assertion validating that `userFooResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userFooResolverType satisfies (
+  args: undefined,
+  context: ITestResolverContextType,
+) => LiveState<unknown | null | undefined>);
 export type barFragment$data = {
   readonly foo: ReturnType<ReturnType<typeof userFooResolverType>["read"]> | null | undefined;
   readonly " $fragmentType": "barFragment";

compiler/crates/relay-typegen/src/typescript.rs

@@ -13,6 +13,8 @@ use intern::intern;
 use itertools::Itertools;
 use relay_config::TypegenConfig;
 
+use crate::writer::FunctionTypeAssertion;
+use crate::writer::KeyValuePairProp;
 use crate::writer::Prop;
 use crate::writer::SortedASTList;
 use crate::writer::SortedStringKeyList;
@@ -77,11 +79,11 @@ impl Writer for TypeScriptPrinter {
             AST::ReturnTypeOfMethodCall(object, method_name) => {
                 self.write_return_type_of_method_call(object, *method_name)
             }
-            AST::AssertFunctionType(_) => {
-                // TODO: Add proper support for Resolver type generation in
-                // typescript: https://github.com/facebook/relay/issues/4772
-                Ok(())
-            }
+            AST::AssertFunctionType(FunctionTypeAssertion {
+                function_name,
+                arguments,
+                return_type,
+            }) => self.write_assert_function_type(*function_name, arguments, return_type),
             AST::GenericType { outer, inner } => self.write_generic_type(*outer, inner),
             AST::PropertyType {
                 type_,
@@ -364,6 +366,41 @@ impl TypeScriptPrinter {
         }
         write!(&mut self.result, ">")
     }
+
+    fn write_assert_function_type(
+        &mut self,
+        function_name: StringKey,
+        arguments: &[KeyValuePairProp],
+        return_type: &AST,
+    ) -> FmtResult {
+        writeln!(
+            &mut self.result,
+            "// Type assertion validating that `{}` resolver is correctly implemented.",
+            function_name
+        )?;
+        writeln!(
+            &mut self.result,
+            "// A type error here indicates that the type signature of the resolver module is incorrect."
+        )?;
+        if arguments.is_empty() {
+            write!(&mut self.result, "({} satisfies (", function_name)?;
+        } else {
+            writeln!(&mut self.result, "({} satisfies (", function_name)?;
+            self.indentation += 1;
+            for argument in arguments.iter() {
+                self.write_indentation()?;
+                write!(&mut self.result, "{}: ", argument.key)?;
+                self.write(&argument.value)?;
+                writeln!(&mut self.result, ",")?;
+            }
+            self.indentation -= 1;
+        }
+        write!(&mut self.result, ") => ")?;
+        self.write(return_type)?;
+        writeln!(&mut self.result, ");")?;
+
+        Ok(())
+    }
 }
 
 #[cfg(test)]

compiler/crates/relay-typegen/src/visit.rs

@@ -402,13 +402,7 @@ fn generate_resolver_type(
 
     let ast = transform_type_reference_into_ast(&schema_field_type, |_| inner_ast);
 
-    let return_type = if matches!(
-        typegen_context.project_config.typegen_config.language,
-        TypegenLanguage::TypeScript
-    ) {
-        // TODO: Add proper support for Resolver type generation in typescript: https://github.com/facebook/relay/issues/4772
-        AST::Any
-    } else if resolver_metadata.live {
+    let return_type = if resolver_metadata.live {
         runtime_imports.resolver_live_state_type = true;
         AST::GenericType {
             outer: *LIVE_STATE_TYPE,

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/relay-resolver-with-output-type-client-interface.expected

@@ -69,6 +69,11 @@ export type User__pop_star_name$normalization = {
 -------------------------------------------------------------------------------
 import type { FragmentRefs } from "relay-runtime";
 import userPopStarNameResolverType from "PopStarNameResolver";
+// Type assertion validating that `userPopStarNameResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userPopStarNameResolverType satisfies (
+  rootKey: PopStarNameResolverFragment_name$key,
+) => User__pop_star_name$normalization | null | undefined);
 export type Foo_user$data = {
   readonly poppy: {
     readonly name: string | null | undefined;

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/relay-resolver-with-output-type-client-object.expected

@@ -38,6 +38,11 @@ export type User__pop_star_name$normalization = {
 -------------------------------------------------------------------------------
 import type { FragmentRefs } from "relay-runtime";
 import userPopStarNameResolverType from "PopStarNameResolver";
+// Type assertion validating that `userPopStarNameResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userPopStarNameResolverType satisfies (
+  rootKey: PopStarNameResolverFragment_name$key,
+) => User__pop_star_name$normalization | null | undefined);
 export type Foo_user$data = {
   readonly poppy: {
     readonly name: string | null | undefined;

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/relay-resolver-with-output-type-relay-resolver-value-required.expected

@@ -21,6 +21,11 @@ extend type User {
 ==================================== OUTPUT ===================================
 import { FragmentRefs } from "relay-runtime";
 import userPopStarNameResolverType from "PopStarNameResolver";
+// Type assertion validating that `userPopStarNameResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userPopStarNameResolverType satisfies (
+  rootKey: PopStarNameResolverFragment_name$key,
+) => unknown | null | undefined);
 export type Foo_user$data = {
   readonly poppy: NonNullable<ReturnType<typeof userPopStarNameResolverType>>;
   readonly " $fragmentType": "Foo_user";

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/relay-resolver-with-output-type-relay-resolver-value.expected

@@ -21,6 +21,11 @@ extend type User {
 ==================================== OUTPUT ===================================
 import { FragmentRefs } from "relay-runtime";
 import userPopStarNameResolverType from "PopStarNameResolver";
+// Type assertion validating that `userPopStarNameResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(userPopStarNameResolverType satisfies (
+  rootKey: PopStarNameResolverFragment_name$key,
+) => unknown | null | undefined);
 export type Foo_user$data = {
   readonly poppy: ReturnType<typeof userPopStarNameResolverType> | null | undefined;
   readonly " $fragmentType": "Foo_user";

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/semantic_non_null_liked_field_resolver.expected

@@ -29,6 +29,11 @@ export type ClientEdgeQuery_MyFragment_best_friend = {
 -------------------------------------------------------------------------------
 import { FragmentRefs, DataID } from "relay-runtime";
 import clientUserBestFriendResolverType from "bar";
+// Type assertion validating that `clientUserBestFriendResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(clientUserBestFriendResolverType satisfies () => {
+  readonly id: DataID;
+});
 export type MyFragment$data = {
   readonly best_friend: {
     readonly name: string | null | undefined;

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/semantic_non_null_liked_field_weak_resolver.expected

@@ -29,6 +29,9 @@ export type ClientUser__blob$normalization = {
 -------------------------------------------------------------------------------
 import { FragmentRefs } from "relay-runtime";
 import clientUserBlobResolverType from "bar";
+// Type assertion validating that `clientUserBlobResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(clientUserBlobResolverType satisfies () => ClientUser__blob$normalization);
 export type MyFragment$data = {
   readonly blob: {
     readonly data: string | null | undefined;

compiler/crates/relay-typegen/tests/generate_typescript/fixtures/semantic_non_null_scalar_resolver.expected

@@ -13,6 +13,9 @@ type ClientUser {
 ==================================== OUTPUT ===================================
 import { FragmentRefs } from "relay-runtime";
 import clientUserNameResolverType from "bar";
+// Type assertion validating that `clientUserNameResolverType` resolver is correctly implemented.
+// A type error here indicates that the type signature of the resolver module is incorrect.
+(clientUserNameResolverType satisfies () => unknown);
 export type MyFragment$data = {
   readonly name: NonNullable<ReturnType<typeof clientUserNameResolverType>>;
   readonly " $fragmentType": "MyFragment";