fix(IntrospectionType): properly type using TypeKind enum

src/utilities/buildClientSchema.ts

@@ -178,28 +178,26 @@ export function buildClientSchema(
   // Given a type's introspection result, construct the correct
   // GraphQLType instance.
   function buildType(type: IntrospectionType): GraphQLNamedType {
-    // eslint-disable-next-line @typescript-eslint/prefer-optional-chain
-    if (type != null && type.name != null && type.kind != null) {
-      // FIXME: Properly type IntrospectionType, it's a breaking change so fix in v17
-      // eslint-disable-next-line @typescript-eslint/switch-exhaustiveness-check
-      switch (type.kind) {
-        case TypeKind.SCALAR:
-          return buildScalarDef(type);
-        case TypeKind.OBJECT:
-          return buildObjectDef(type);
-        case TypeKind.INTERFACE:
-          return buildInterfaceDef(type);
-        case TypeKind.UNION:
-          return buildUnionDef(type);
-        case TypeKind.ENUM:
-          return buildEnumDef(type);
-        case TypeKind.INPUT_OBJECT:
-          return buildInputObjectDef(type);
-      }
+    switch (type.kind) {
+      case TypeKind.SCALAR:
+        return buildScalarDef(type);
+      case TypeKind.OBJECT:
+        return buildObjectDef(type);
+      case TypeKind.INTERFACE:
+        return buildInterfaceDef(type);
+      case TypeKind.UNION:
+        return buildUnionDef(type);
+      case TypeKind.ENUM:
+        return buildEnumDef(type);
+      case TypeKind.INPUT_OBJECT:
+        return buildInputObjectDef(type);
     }
-    const typeStr = inspect(type);
+    // Unreachable.
+    // @ts-expect-error
     throw new Error(
-      `Invalid or incomplete introspection result. Ensure that a full introspection query is used in order to build a client schema: ${typeStr}.`,
+      `Invalid or incomplete introspection result. Ensure that a full introspection query is used in order to build a client schema: ${inspect(
+        type,
+      )}.`,
     );
   }
 

src/utilities/getIntrospectionQuery.ts

@@ -2,6 +2,8 @@ import type { Maybe } from '../jsutils/Maybe.js';
 
 import type { DirectiveLocation } from '../language/directiveLocation.js';
 
+import type { TypeKind } from '../type/introspection.js';
+
 export interface IntrospectionOptions {
   /**
    * Whether to include descriptions in the introspection result.
@@ -218,14 +220,14 @@ export type IntrospectionInputType =
   | IntrospectionInputObjectType;
 
 export interface IntrospectionScalarType {
-  readonly kind: 'SCALAR';
+  readonly kind: TypeKind.SCALAR;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly specifiedByURL?: Maybe<string>;
 }
 
 export interface IntrospectionObjectType {
-  readonly kind: 'OBJECT';
+  readonly kind: TypeKind.OBJECT;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly fields: ReadonlyArray<IntrospectionField>;
@@ -235,7 +237,7 @@ export interface IntrospectionObjectType {
 }
 
 export interface IntrospectionInterfaceType {
-  readonly kind: 'INTERFACE';
+  readonly kind: TypeKind.INTERFACE;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly fields: ReadonlyArray<IntrospectionField>;
@@ -248,7 +250,7 @@ export interface IntrospectionInterfaceType {
 }
 
 export interface IntrospectionUnionType {
-  readonly kind: 'UNION';
+  readonly kind: TypeKind.UNION;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly possibleTypes: ReadonlyArray<
@@ -257,14 +259,14 @@ export interface IntrospectionUnionType {
 }
 
 export interface IntrospectionEnumType {
-  readonly kind: 'ENUM';
+  readonly kind: TypeKind.ENUM;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly enumValues: ReadonlyArray<IntrospectionEnumValue>;
 }
 
 export interface IntrospectionInputObjectType {
-  readonly kind: 'INPUT_OBJECT';
+  readonly kind: TypeKind.INPUT_OBJECT;
   readonly name: string;
   readonly description?: Maybe<string>;
   readonly inputFields: ReadonlyArray<IntrospectionInputValue>;
@@ -274,14 +276,14 @@ export interface IntrospectionInputObjectType {
 export interface IntrospectionListTypeRef<
   T extends IntrospectionTypeRef = IntrospectionTypeRef,
 > {
-  readonly kind: 'LIST';
+  readonly kind: TypeKind.LIST;
   readonly ofType: T;
 }
 
 export interface IntrospectionNonNullTypeRef<
   T extends IntrospectionTypeRef = IntrospectionTypeRef,
 > {
-  readonly kind: 'NON_NULL';
+  readonly kind: TypeKind.NON_NULL;
   readonly ofType: T;
 }