Improve typings for validation functions

Split out from graphql#1438

src/validation/__tests__/harness.js

@@ -421,30 +421,30 @@ export const testSchema = new GraphQLSchema({
   ],
 });
 
-function expectValid(schema, rules, queryString) {
-  const errors = validate(schema, parse(queryString), rules);
+function expectValid(schema, rule, queryString) {
+  const errors = validate(schema, parse(queryString), [rule]);
   expect(errors).to.deep.equal([], 'Should validate');
 }
 
-function expectInvalid(schema, rules, queryString, expectedErrors) {
-  const errors = validate(schema, parse(queryString), rules);
+function expectInvalid(schema, rule, queryString, expectedErrors) {
+  const errors = validate(schema, parse(queryString), [rule]);
   expect(errors).to.have.length.of.at.least(1, 'Should not validate');
   expect(errors).to.deep.equal(expectedErrors);
   return errors;
 }
 
 export function expectPassesRule(rule, queryString) {
-  return expectValid(testSchema, [rule], queryString);
+  return expectValid(testSchema, rule, queryString);
 }
 
 export function expectFailsRule(rule, queryString, errors) {
-  return expectInvalid(testSchema, [rule], queryString, errors);
+  return expectInvalid(testSchema, rule, queryString, errors);
 }
 
-export function expectPassesRuleWithSchema(schema, rule, queryString, errors) {
-  return expectValid(schema, [rule], queryString, errors);
+export function expectPassesRuleWithSchema(schema, rule, queryString) {
+  return expectValid(schema, rule, queryString);
 }
 
 export function expectFailsRuleWithSchema(schema, rule, queryString, errors) {
-  return expectInvalid(schema, [rule], queryString, errors);
+  return expectInvalid(schema, rule, queryString, errors);
 }

src/validation/specifiedRules.js

@@ -7,6 +7,9 @@
  * @flow strict
  */
 
+import type { ASTVisitor } from '../language/visitor';
+import type ValidationContext from './ValidationContext';
+
 // Spec Section: "Executable Definitions"
 import { ExecutableDefinitions } from './rules/ExecutableDefinitions';
 
@@ -85,15 +88,13 @@ import { OverlappingFieldsCanBeMerged } from './rules/OverlappingFieldsCanBeMerg
 // Spec Section: "Input Object Field Uniqueness"
 import { UniqueInputFieldNames } from './rules/UniqueInputFieldNames';
 
-import type ValidationContext from './ValidationContext';
-
 /**
  * This set includes all validation rules defined by the GraphQL spec.
  *
  * The order of the rules in this list has been adjusted to lead to the
  * most clear output when encountering multiple validation errors.
  */
-export const specifiedRules: Array<(context: ValidationContext) => any> = [
+export const specifiedRules: Array<(ValidationContext) => ASTVisitor> = [
   ExecutableDefinitions,
   UniqueOperationNames,
   LoneAnonymousOperation,

src/validation/validate.js

@@ -9,6 +9,7 @@
 
 import invariant from '../jsutils/invariant';
 import type { GraphQLError } from '../error';
+import type { ASTVisitor } from '../language/visitor';
 import { visit, visitInParallel, visitWithTypeInfo } from '../language/visitor';
 import type { DocumentNode } from '../language/ast';
 import type { GraphQLSchema } from '../type/schema';
@@ -36,7 +37,7 @@ import ValidationContext from './ValidationContext';
 export function validate(
   schema: GraphQLSchema,
   documentAST: DocumentNode,
-  rules?: $ReadOnlyArray<any> = specifiedRules,
+  rules?: $ReadOnlyArray<(ValidationContext) => ASTVisitor> = specifiedRules,
   typeInfo?: TypeInfo = new TypeInfo(schema),
 ): $ReadOnlyArray<GraphQLError> {
   invariant(documentAST, 'Must provide document');