Added .d.ts files for test utils

src/__fixtures__/index.d.ts

@@ -0,0 +1,4 @@
+export declare const bigSchemaSDL: string;
+export declare const bigSchemaIntrospectionResult: { data: unknown };
+export declare const kitchenSinkSDL: string;
+export declare const kitchenSinkQuery: string;

src/error/GraphQLError.d.ts

@@ -13,7 +13,7 @@ import { SourceLocation } from '../language/location';
 export class GraphQLError extends Error {
   constructor(
     message: string,
-    nodes?: ReadonlyArray<ASTNode> | ASTNode,
+    nodes?: Maybe<ReadonlyArray<ASTNode> | ASTNode>,
     source?: Maybe<Source>,
     positions?: Maybe<ReadonlyArray<number>>,
     path?: Maybe<ReadonlyArray<string | number>>,

src/jsutils/ObjMap.d.ts

@@ -0,0 +1,15 @@
+export interface ObjMap<T> {
+  [key: string]: T;
+  __proto__: never;
+}
+
+export type ObjMapLike<T> = ObjMap<T> | { [key: string]: T };
+
+export interface ReadOnlyObjMap<T> {
+  readonly [key: string]: T;
+  __proto__: never;
+}
+
+export type ReadOnlyObjMapLike<T> =
+  | ReadOnlyObjMap<T>
+  | { readonly [key: string]: T };

src/jsutils/didYouMean.d.ts

@@ -0,0 +1,10 @@
+/**
+ * Given [ A, B, C ] return ' Did you mean A, B, or C?'.
+ */
+declare function didYouMean(suggestions: ReadonlyArray<string>): string;
+declare function didYouMean(
+  subMessage: string,
+  suggestions: ReadonlyArray<string>,
+): string;
+
+export default didYouMean;

src/jsutils/identityFunc.d.ts

@@ -0,0 +1,4 @@
+/**
+ * Returns the first argument it receives.
+ */
+export default function identityFunc<T>(x?: T): T;

src/jsutils/inspect.d.ts

@@ -0,0 +1,4 @@
+/**
+ * Used to print values in error messages.
+ */
+export default function inspect(value: any): string;

src/jsutils/instanceOf.d.ts

@@ -0,0 +1,5 @@
+/**
+ * A replacement for instanceof which includes an error warning when multi-realm
+ * constructors are detected.
+ */
+export default function instanceOf(value: any, constructor: any): boolean;

src/jsutils/invariant.d.ts

@@ -0,0 +1 @@
+export default function invariant(condition: any, message?: string): void;

src/jsutils/isCollection.d.ts

@@ -0,0 +1,22 @@
+/**
+ * Returns true if the provided object is an Object (i.e. not a string literal)
+ * and is either Iterable or Array-like.
+ *
+ * This may be used in place of [Array.isArray()][isArray] to determine if an
+ * object should be iterated-over. It always excludes string literals and
+ * includes Arrays (regardless of if it is Iterable). It also includes other
+ * Array-like objects such as NodeList, TypedArray, and Buffer.
+ *
+ * @example
+ *
+ * isCollection([ 1, 2, 3 ]) // true
+ * isCollection('ABC') // false
+ * isCollection({ length: 1, 0: 'Alpha' }) // true
+ * isCollection({ key: 'value' }) // false
+ * isCollection(new Map()) // true
+ *
+ * @param obj
+ *   An Object value which might implement the Iterable or Array-like protocols.
+ * @return true if Iterable or Array-like Object.
+ */
+export default function isCollection(obj: any): boolean;

src/jsutils/isObjectLike.d.ts

@@ -0,0 +1,5 @@
+/**
+ * Return true if `value` is object-like. A value is object-like if it's not
+ * `null` and has a `typeof` result of "object".
+ */
+export default function isObjectLike(value: any): boolean;

src/jsutils/nodejsCustomInspectSymbol.d.ts

@@ -0,0 +1,3 @@
+declare const nodejsCustomInspectSymbol: symbol | undefined;
+
+export default nodejsCustomInspectSymbol;

src/jsutils/suggestionList.d.ts

@@ -0,0 +1,8 @@
+/**
+ * Given an invalid input string and a list of valid options, returns a filtered
+ * list of valid options sorted based on their similarity with the input.
+ */
+export default function suggestionList(
+  input: string,
+  options: ReadonlyArray<string>,
+): Array<string>;

src/jsutils/toObjMap.d.ts

@@ -0,0 +1,11 @@
+import {
+  ObjMap,
+  ObjMapLike,
+  ReadOnlyObjMap,
+  ReadOnlyObjMapLike,
+} from './ObjMap';
+
+declare function toObjMap<T>(obj: ObjMapLike<T>): ObjMap<T>;
+declare function toObjMap<T>(obj: ReadOnlyObjMapLike<T>): ReadOnlyObjMap<T>;
+
+export default toObjMap;