Use flow %checks to reduce occurance of :any

This uses a pre-release flow feature to provide predicate functions with more type checking power. It also breaks apart some functions into multiple declare function statements for cases where more specific input types result in more specific output types.

Author: leebyron

src/execution/execute.js

@@ -18,14 +18,11 @@ import { typeFromAST } from '../utilities/typeFromAST';
 import * as Kind from '../language/kinds';
 import { getVariableValues, getArgumentValues } from './values';
 import {
-  GraphQLScalarType,
   GraphQLObjectType,
-  GraphQLEnumType,
   GraphQLList,
   GraphQLNonNull,
-  GraphQLInterfaceType,
-  GraphQLUnionType,
-  isAbstractType
+  isAbstractType,
+  isLeafType,
 } from '../type/definition';
 import type {
   GraphQLType,
@@ -527,8 +524,7 @@ function doesFragmentConditionMatch(
     return true;
   }
   if (isAbstractType(conditionalType)) {
-    const abstractType = ((conditionalType: any): GraphQLAbstractType);
-    return exeContext.schema.isPossibleType(abstractType, type);
+    return exeContext.schema.isPossibleType(conditionalType, type);
   }
   return false;
 }
@@ -831,15 +827,13 @@ function completeValue(
 
   // If field type is a leaf type, Scalar or Enum, serialize to a valid value,
   // returning null if serialization is not possible.
-  if (returnType instanceof GraphQLScalarType ||
-      returnType instanceof GraphQLEnumType) {
+  if (isLeafType(returnType)) {
     return completeLeafValue(returnType, result);
   }
 
   // If field type is an abstract type, Interface or Union, determine the
   // runtime Object type and complete for that type.
-  if (returnType instanceof GraphQLInterfaceType ||
-      returnType instanceof GraphQLUnionType) {
+  if (isAbstractType(returnType)) {
     return completeAbstractValue(
       exeContext,
       returnType,

src/execution/values.js

@@ -57,15 +57,14 @@ export function getVariableValues(
   for (let i = 0; i < varDefNodes.length; i++) {
     const varDefNode = varDefNodes[i];
     const varName = varDefNode.variable.name.value;
-    let varType = typeFromAST(schema, varDefNode.type);
+    const varType = typeFromAST(schema, varDefNode.type);
     if (!isInputType(varType)) {
       throw new GraphQLError(
         `Variable "$${varName}" expected value of type ` +
         `"${print(varDefNode.type)}" which cannot be used as an input type.`,
         [ varDefNode.type ]
       );
     }
-    varType = ((varType: any): GraphQLInputType);
 
     const value = inputs[varName];
     if (isInvalid(value)) {

src/type/definition.js

@@ -72,12 +72,13 @@ export type GraphQLInputType =
     GraphQLList<GraphQLInputType>
   >;
 
-export function isInputType(type: ?GraphQLType): boolean {
-  const namedType = getNamedType(type);
+export function isInputType(type: ?GraphQLType): boolean %checks {
   return (
-    namedType instanceof GraphQLScalarType ||
-    namedType instanceof GraphQLEnumType ||
-    namedType instanceof GraphQLInputObjectType
+    type instanceof GraphQLScalarType ||
+    type instanceof GraphQLEnumType ||
+    type instanceof GraphQLInputObjectType ||
+    type instanceof GraphQLNonNull && isInputType(type.ofType) ||
+    type instanceof GraphQLList && isInputType(type.ofType)
   );
 }
 
@@ -86,7 +87,7 @@ export function assertInputType(type: ?GraphQLType): GraphQLInputType {
     isInputType(type),
     `Expected ${String(type)} to be a GraphQL input type.`
   );
-  return (type: any);
+  return type;
 }
 
 /**
@@ -108,14 +109,15 @@ export type GraphQLOutputType =
     GraphQLList<GraphQLOutputType>
   >;
 
-export function isOutputType(type: ?GraphQLType): boolean {
-  const namedType = getNamedType(type);
+export function isOutputType(type: ?GraphQLType): boolean %checks {
   return (
-    namedType instanceof GraphQLScalarType ||
-    namedType instanceof GraphQLObjectType ||
-    namedType instanceof GraphQLInterfaceType ||
-    namedType instanceof GraphQLUnionType ||
-    namedType instanceof GraphQLEnumType
+    type instanceof GraphQLScalarType ||
+    type instanceof GraphQLObjectType ||
+    type instanceof GraphQLInterfaceType ||
+    type instanceof GraphQLUnionType ||
+    type instanceof GraphQLEnumType ||
+    type instanceof GraphQLNonNull && isOutputType(type.ofType) ||
+    type instanceof GraphQLList && isOutputType(type.ofType)
   );
 }
 
@@ -124,7 +126,7 @@ export function assertOutputType(type: ?GraphQLType): GraphQLOutputType {
     isOutputType(type),
     `Expected ${String(type)} to be a GraphQL output type.`,
   );
-  return (type: any);
+  return type;
 }
 
 /**
@@ -134,7 +136,7 @@ export type GraphQLLeafType =
   GraphQLScalarType |
   GraphQLEnumType;
 
-export function isLeafType(type: ?GraphQLType): boolean {
+export function isLeafType(type: ?GraphQLType): boolean %checks {
   return (
     type instanceof GraphQLScalarType ||
     type instanceof GraphQLEnumType
@@ -146,7 +148,7 @@ export function assertLeafType(type: ?GraphQLType): GraphQLLeafType {
     isLeafType(type),
     `Expected ${String(type)} to be a GraphQL leaf type.`,
   );
-  return (type: any);
+  return type;
 }
 
 /**
@@ -157,7 +159,7 @@ export type GraphQLCompositeType =
   GraphQLInterfaceType |
   GraphQLUnionType;
 
-export function isCompositeType(type: ?GraphQLType): boolean {
+export function isCompositeType(type: ?GraphQLType): boolean %checks {
   return (
     type instanceof GraphQLObjectType ||
     type instanceof GraphQLInterfaceType ||
@@ -170,7 +172,7 @@ export function assertCompositeType(type: ?GraphQLType): GraphQLCompositeType {
     isCompositeType(type),
     `Expected ${String(type)} to be a GraphQL composite type.`,
   );
-  return (type: any);
+  return type;
 }
 
 /**
@@ -180,7 +182,7 @@ export type GraphQLAbstractType =
   GraphQLInterfaceType |
   GraphQLUnionType;
 
-export function isAbstractType(type: ?GraphQLType): boolean {
+export function isAbstractType(type: ?GraphQLType): boolean %checks {
   return (
     type instanceof GraphQLInterfaceType ||
     type instanceof GraphQLUnionType
@@ -192,7 +194,7 @@ export function assertAbstractType(type: ?GraphQLType): GraphQLAbstractType {
     isAbstractType(type),
     `Expected ${String(type)} to be a GraphQL abstract type.`,
   );
-  return (type: any);
+  return type;
 }
 
 /**
@@ -224,7 +226,7 @@ export type GraphQLNamedType =
   GraphQLEnumType |
   GraphQLInputObjectType;
 
-export function isNamedType(type: ?GraphQLType): boolean {
+export function isNamedType(type: ?GraphQLType): boolean %checks {
   return (
     type instanceof GraphQLScalarType ||
     type instanceof GraphQLObjectType ||
@@ -240,18 +242,24 @@ export function assertNamedType(type: ?GraphQLType): GraphQLNamedType {
     isNamedType(type),
     `Expected ${String(type)} to be a GraphQL named type.`,
   );
-  return (type: any);
+  return type;
 }
 
-export function getNamedType(type: ?GraphQLType): ?GraphQLNamedType {
-  let unmodifiedType = type;
-  while (
-    unmodifiedType instanceof GraphQLList ||
-    unmodifiedType instanceof GraphQLNonNull
-  ) {
-    unmodifiedType = unmodifiedType.ofType;
+/* eslint-disable no-redeclare */
+declare function getNamedType(type: void | null): void;
+declare function getNamedType(type: GraphQLType): GraphQLNamedType;
+export function getNamedType(type) {
+/* eslint-enable no-redeclare */
+  if (type) {
+    let unmodifiedType = type;
+    while (
+      unmodifiedType instanceof GraphQLList ||
+      unmodifiedType instanceof GraphQLNonNull
+    ) {
+      unmodifiedType = unmodifiedType.ofType;
+    }
+    return unmodifiedType;
   }
-  return unmodifiedType;
 }
 
 
@@ -556,7 +564,7 @@ function isPlainObj(obj) {
 }
 
 // If a resolver is defined, it must be a function.
-function isValidResolver(resolver: any): boolean {
+function isValidResolver(resolver: mixed): boolean {
   return (resolver == null || typeof resolver === 'function');
 }
 

src/type/introspection.js

@@ -20,6 +20,7 @@ import {
   GraphQLInputObjectType,
   GraphQLList,
   GraphQLNonNull,
+  isAbstractType,
 } from './definition';
 import { GraphQLString, GraphQLBoolean } from './scalars';
 import { DirectiveLocation } from './directives';
@@ -267,8 +268,7 @@ export const __Type = new GraphQLObjectType({
     possibleTypes: {
       type: new GraphQLList(new GraphQLNonNull(__Type)),
       resolve(type, args, context, { schema }) {
-        if (type instanceof GraphQLInterfaceType ||
-            type instanceof GraphQLUnionType) {
+        if (isAbstractType(type)) {
           return schema.getPossibleTypes(type);
         }
       }

src/utilities/TypeInfo.js

@@ -17,7 +17,6 @@ import {
   getNamedType,
   GraphQLObjectType,
   GraphQLInterfaceType,
-  GraphQLUnionType,
   GraphQLInputObjectType,
   GraphQLEnumType,
   GraphQLList,
@@ -120,9 +119,7 @@ export class TypeInfo {
       case Kind.SELECTION_SET:
         const namedType = getNamedType(this.getType());
         this._parentTypeStack.push(
-          isCompositeType(namedType) ?
-            ((namedType: any): GraphQLCompositeType) :
-            undefined
+          isCompositeType(namedType) ? namedType : undefined
         );
         break;
       case Kind.FIELD:
@@ -155,17 +152,13 @@ export class TypeInfo {
           typeFromAST(schema, typeConditionAST) :
           this.getType();
         this._typeStack.push(
-          isOutputType(outputType) ?
-            ((outputType: any): GraphQLOutputType) :
-            undefined
+          isOutputType(outputType) ? outputType : undefined
         );
         break;
       case Kind.VARIABLE_DEFINITION:
         const inputType = typeFromAST(schema, node.type);
         this._inputTypeStack.push(
-          isInputType(inputType) ?
-            ((inputType: any): GraphQLInputType) :
-            undefined
+          isInputType(inputType) ? inputType : undefined
         );
         break;
       case Kind.ARGUMENT:
@@ -264,11 +257,7 @@ function getFieldDef(
       schema.getQueryType() === parentType) {
     return TypeMetaFieldDef;
   }
-  if (name === TypeNameMetaFieldDef.name &&
-      (parentType instanceof GraphQLObjectType ||
-       parentType instanceof GraphQLInterfaceType ||
-       parentType instanceof GraphQLUnionType)
-  ) {
+  if (name === TypeNameMetaFieldDef.name && isCompositeType(parentType)) {
     return TypeNameMetaFieldDef;
   }
   if (parentType instanceof GraphQLObjectType ||

src/utilities/buildASTSchema.js

@@ -68,8 +68,8 @@ import {
   GraphQLInputObjectType,
   GraphQLList,
   GraphQLNonNull,
-  isInputType,
-  isOutputType,
+  assertInputType,
+  assertOutputType,
 } from '../type/definition';
 
 import type {
@@ -299,15 +299,11 @@ export function buildASTSchema(ast: DocumentNode): GraphQLSchema {
   }
 
   function produceInputType(typeNode: TypeNode): GraphQLInputType {
-    const type = produceType(typeNode);
-    invariant(isInputType(type), 'Expected Input type.');
-    return (type: any);
+    return assertInputType(produceType(typeNode));
   }
 
   function produceOutputType(typeNode: TypeNode): GraphQLOutputType {
-    const type = produceType(typeNode);
-    invariant(isOutputType(type), 'Expected Output type.');
-    return (type: any);
+    return assertOutputType(produceType(typeNode));
   }
 
   function produceObjectType(typeNode: TypeNode): GraphQLObjectType {

src/utilities/buildClientSchema.js

@@ -162,7 +162,7 @@ export function buildClientSchema(
       isInputType(type),
       'Introspection must provide input type for arguments.'
     );
-    return (type: any);
+    return type;
   }
 
   function getOutputType(typeRef: IntrospectionTypeRef): GraphQLOutputType {
@@ -171,7 +171,7 @@ export function buildClientSchema(
       isOutputType(type),
       'Introspection must provide output type for fields.'
     );
-    return (type: any);
+    return type;
   }
 
   function getObjectType(typeRef: IntrospectionTypeRef): GraphQLObjectType {
@@ -180,7 +180,7 @@ export function buildClientSchema(
       type instanceof GraphQLObjectType,
       'Introspection must provide object type for possibleTypes.'
     );
-    return (type: any);
+    return type;
   }
 
   function getInterfaceType(
@@ -191,7 +191,7 @@ export function buildClientSchema(
       type instanceof GraphQLInterfaceType,
       'Introspection must provide interface type for interfaces.'
     );
-    return (type: any);
+    return type;
   }