Flow: add missing names to arguments of function types (#3072)

In preparation to TS convertion

src/execution/values.js

@@ -74,7 +74,7 @@ function coerceVariableValues(
   schema: GraphQLSchema,
   varDefNodes: $ReadOnlyArray<VariableDefinitionNode>,
   inputs: { +[variable: string]: mixed, ... },
-  onError: (GraphQLError) => void,
+  onError: (error: GraphQLError) => void,
 ): { [variable: string]: mixed, ... } {
   const coercedValues = {};
   for (const varDefNode of varDefNodes) {

src/jsutils/instanceOf.js

@@ -4,7 +4,7 @@
  * See: https://expressjs.com/en/advanced/best-practice-performance.html#set-node_env-to-production
  * See: https://webpack.js.org/guides/production/
  */
-export const instanceOf: (mixed, Constructor) => boolean =
+export const instanceOf: (value: mixed, constructor: Constructor) => boolean =
   process.env.NODE_ENV === 'production'
     ? // istanbul ignore next (See: 'https://github.com/graphql/graphql-js/issues/2317')
       function instanceOf(value: mixed, constructor: Constructor): boolean {

src/jsutils/memoize3.js

@@ -6,7 +6,7 @@ export function memoize3<
   A2: { ... } | $ReadOnlyArray<mixed>,
   A3: { ... } | $ReadOnlyArray<mixed>,
   R,
->(fn: (A1, A2, A3) => R): (A1, A2, A3) => R {
+>(fn: (a1: A1, a2: A2, a3: A3) => R): (a1: A1, a2: A2, a3: A3) => R {
   let cache0;
 
   return function memoized(a1, a2, a3) {

src/jsutils/promiseReduce.js

@@ -11,7 +11,7 @@ import { isPromise } from './isPromise';
  */
 export function promiseReduce<T, U>(
   values: $ReadOnlyArray<T>,
-  callback: (U, T) => PromiseOrValue<U>,
+  callback: (accumulator: U, currentValue: T) => PromiseOrValue<U>,
   initialValue: PromiseOrValue<U>,
 ): PromiseOrValue<U> {
   return values.reduce(

src/language/__tests__/predicates-test.js

@@ -21,7 +21,7 @@ const allASTNodes: Array<ASTNode> = Object.values(Kind).map(
   (kind) => ({ kind }: any),
 );
 
-function filterNodes(predicate: (ASTNode) => boolean): Array<string> {
+function filterNodes(predicate: (node: ASTNode) => boolean): Array<string> {
   return allASTNodes.filter(predicate).map(({ kind }) => kind);
 }
 

src/language/visitor.js

@@ -11,7 +11,7 @@ export type ASTVisitor = $Shape<EnterLeaveVisitor<ASTNode> & KindVisitor>;
 
 type KindVisitor = $ObjMap<
   ASTKindToNode,
-  <Node>(Node) => ASTVisitFn<Node> | EnterLeaveVisitor<Node>,
+  <Node>(node: Node) => ASTVisitFn<Node> | EnterLeaveVisitor<Node>,
 >;
 
 type EnterLeaveVisitor<TVisitedNode: ASTNode> = {|

src/subscription/__tests__/mapAsyncIterator-test.js

@@ -276,7 +276,7 @@ describe('mapAsyncIterator', () => {
       .with.property('message', 'Goodbye');
   });
 
-  async function testClosesSourceWithMapper<T>(mapper: (number) => T) {
+  async function testClosesSourceWithMapper<T>(mapper: (value: number) => T) {
     let didVisitFinally = false;
 
     async function* source() {

src/subscription/__tests__/simplePubSub.js

@@ -3,7 +3,7 @@
  * PubSub system for tests.
  */
 export class SimplePubSub<T> {
-  _subscribers: Set<(T) => void>;
+  _subscribers: Set<(value: T) => void>;
 
   constructor() {
     this._subscribers = new Set();
@@ -16,7 +16,7 @@ export class SimplePubSub<T> {
     return this._subscribers.size > 0;
   }
 
-  getSubscriber<R>(transform: (T) => R): AsyncGenerator<R, void, void> {
+  getSubscriber<R>(transform: (value: T) => R): AsyncGenerator<R, void, void> {
     const pullQueue: Array<(result: IteratorResult<R, void>) => void> = [];
     const pushQueue = [];
     let listening = true;

src/subscription/mapAsyncIterator.js

@@ -6,7 +6,7 @@ import type { PromiseOrValue } from '../jsutils/PromiseOrValue';
  */
 export function mapAsyncIterator<T, U, R = void>(
   iterable: AsyncGenerator<T, R, void> | AsyncIterable<T>,
-  callback: (T) => PromiseOrValue<U>,
+  callback: (value: T) => PromiseOrValue<U>,
 ): AsyncGenerator<U, R, void> {
   // $FlowIssue[incompatible-use]
   const iterator = iterable[Symbol.asyncIterator]();

src/type/validate.js

@@ -557,7 +557,7 @@ function validateInputFields(
 
 function createInputObjectCircularRefsValidator(
   context: SchemaValidationContext,
-): (GraphQLInputObjectType) => void {
+): (inputObj: GraphQLInputObjectType) => void {
   // Modified copy of algorithm from 'src/validation/rules/NoFragmentCycles.js'.
   // Tracks already visited types to maintain O(N) and to ensure that cycles
   // are not redundantly reported.

src/utilities/lexicographicSortSchema.js

@@ -156,7 +156,10 @@ export function lexicographicSortSchema(schema: GraphQLSchema): GraphQLSchema {
   }
 }
 
-function sortObjMap<T, R>(map: ObjMap<T>, sortValueFn: (T) => R): ObjMap<R> {
+function sortObjMap<T, R>(
+  map: ObjMap<T>,
+  sortValueFn: (value: T) => R,
+): ObjMap<R> {
   const sortedMap = Object.create(null);
   const sortedEntries = sortBy(Object.entries(map), ([key]) => key);
   for (const [key, value] of sortedEntries) {
@@ -173,7 +176,7 @@ function sortByName<T: { +name: string, ... }>(
 
 function sortBy<T>(
   array: $ReadOnlyArray<T>,
-  mapToKey: (T) => string,
+  mapToKey: (item: T) => string,
 ): Array<T> {
   return array.slice().sort((obj1, obj2) => {
     const key1 = mapToKey(obj1);

src/validation/ValidationContext.js

@@ -128,7 +128,7 @@ export class ASTValidationContext {
   }
 }
 
-export type ASTValidationRule = (ASTValidationContext) => ASTVisitor;
+export type ASTValidationRule = (context: ASTValidationContext) => ASTVisitor;
 
 export class SDLValidationContext extends ASTValidationContext {
   _schema: ?GraphQLSchema;
@@ -147,7 +147,7 @@ export class SDLValidationContext extends ASTValidationContext {
   }
 }
 
-export type SDLValidationRule = (SDLValidationContext) => ASTVisitor;
+export type SDLValidationRule = (context: SDLValidationContext) => ASTVisitor;
 
 export class ValidationContext extends ASTValidationContext {
   _schema: GraphQLSchema;
@@ -246,4 +246,4 @@ export class ValidationContext extends ASTValidationContext {
   }
 }
 
-export type ValidationRule = (ValidationContext) => ASTVisitor;
+export type ValidationRule = (context: ValidationContext) => ASTVisitor;