Cleanup Enums (#1201)

* Convert 'Kind' to object and expose 'KindEnum'

* Create 'TokenKindEnum' type.

* Move 'literalTok' outside of 'readToken'

* Avoid using enums as runtime values

Enum values are best left as representative opaque values, so we should avoid `value.length`. Minor variable name changes to preserve existing formatting

* Which makes literalTok uncalled

Author: IvanGoncharov

src/execution/execute.js

@@ -20,7 +20,7 @@ import type { ObjMap } from '../jsutils/ObjMap';
 import type { MaybePromise } from '../jsutils/MaybePromise';
 
 import { typeFromAST } from '../utilities/typeFromAST';
-import * as Kind from '../language/kinds';
+import { Kind } from '../language/kinds';
 import {
   getVariableValues,
   getArgumentValues,

src/execution/values.js

@@ -14,7 +14,7 @@ import keyMap from '../jsutils/keyMap';
 import { coerceValue } from '../utilities/coerceValue';
 import { typeFromAST } from '../utilities/typeFromAST';
 import { valueFromAST } from '../utilities/valueFromAST';
-import * as Kind from '../language/kinds';
+import { Kind } from '../language/kinds';
 import { print } from '../language/printer';
 import { isInputType, isNonNullType } from '../type/definition';
 import type { ObjMap } from '../jsutils/ObjMap';

src/index.js

@@ -247,6 +247,8 @@ export type {
   TypeExtensionNode,
   ObjectTypeExtensionNode,
   DirectiveDefinitionNode,
+  KindEnum,
+  TokenKindEnum,
   DirectiveLocationEnum,
 } from './language';
 

src/language/__tests__/parser-test.js

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import * as Kind from '../kinds';
+import { Kind } from '../kinds';
 import { expect } from 'chai';
 import { describe, it } from 'mocha';
 import { parse, parseValue, parseType } from '../parser';

src/language/__tests__/visitor-test.js

@@ -15,7 +15,7 @@ import { join } from 'path';
 import { TypeInfo } from '../../utilities/TypeInfo';
 import { testSchema } from '../../validation/__tests__/harness';
 import { getNamedType, isCompositeType } from '../../type';
-import * as Kind from '../kinds';
+import { Kind } from '../kinds';
 
 function getNodeByPath(ast, path) {
   let result = ast;

src/language/ast.js

@@ -8,6 +8,7 @@
  */
 
 import type { Source } from './source';
+import type { TokenKindEnum } from './lexer';
 
 /**
  * Contains a range of UTF-8 character offsets and token references that
@@ -40,35 +41,6 @@ export type Location = {
   +source: Source,
 };
 
-/**
- * Represents the different kinds of tokens in a GraphQL document.
- * This type is not inlined in `Token` to fix syntax highlighting on GitHub
- * *only*.
- */
-type TokenKind =
-  | '<SOF>'
-  | '<EOF>'
-  | '!'
-  | '$'
-  | '&'
-  | '('
-  | ')'
-  | '...'
-  | ':'
-  | '='
-  | '@'
-  | '['
-  | ']'
-  | '{'
-  | '|'
-  | '}'
-  | 'Name'
-  | 'Int'
-  | 'Float'
-  | 'String'
-  | 'BlockString'
-  | 'Comment';
-
 /**
  * Represents a range of characters represented by a lexical token
  * within a Source.
@@ -77,7 +49,7 @@ export type Token = {
   /**
    * The kind of Token.
    */
-  +kind: TokenKind,
+  +kind: TokenKindEnum,
 
   /**
    * The character offset at which this Node begins.

src/language/directiveLocation.js

@@ -10,7 +10,7 @@
 /**
  * The set of allowed directive location values.
  */
-export const DirectiveLocation = {
+export const DirectiveLocation = Object.freeze({
   // Request Definitions
   QUERY: 'QUERY',
   MUTATION: 'MUTATION',
@@ -31,9 +31,9 @@ export const DirectiveLocation = {
   ENUM_VALUE: 'ENUM_VALUE',
   INPUT_OBJECT: 'INPUT_OBJECT',
   INPUT_FIELD_DEFINITION: 'INPUT_FIELD_DEFINITION',
-};
+});
 
 /**
  * The enum type representing the directive location values.
  */
-export type DirectiveLocationEnum = $Keys<typeof DirectiveLocation>;
+export type DirectiveLocationEnum = $Values<typeof DirectiveLocation>;

src/language/index.js

@@ -9,8 +9,8 @@
 
 export { getLocation } from './location';
 export type { SourceLocation } from './location';
-import * as Kind from './kinds';
-export { Kind };
+export { Kind } from './kinds';
+export type { KindEnum } from './kinds';
 export { createLexer, TokenKind } from './lexer';
 export { parse, parseValue, parseType } from './parser';
 export { print } from './printer';
@@ -24,7 +24,7 @@ export {
 } from './visitor';
 export type { ASTVisitor, Visitor, VisitFn, VisitorKeyMap } from './visitor';
 
-export type { Lexer } from './lexer';
+export type { Lexer, TokenKindEnum } from './lexer';
 export type { ParseOptions } from './parser';
 
 export type {

src/language/kinds.js

@@ -7,74 +7,74 @@
  * @flow
  */
 
-// Name
-
-export const NAME = 'Name';
-
-// Document
-
-export const DOCUMENT = 'Document';
-export const OPERATION_DEFINITION = 'OperationDefinition';
-export const VARIABLE_DEFINITION = 'VariableDefinition';
-export const VARIABLE = 'Variable';
-export const SELECTION_SET = 'SelectionSet';
-export const FIELD = 'Field';
-export const ARGUMENT = 'Argument';
-
-// Fragments
-
-export const FRAGMENT_SPREAD = 'FragmentSpread';
-export const INLINE_FRAGMENT = 'InlineFragment';
-export const FRAGMENT_DEFINITION = 'FragmentDefinition';
-
-// Values
-
-export const INT = 'IntValue';
-export const FLOAT = 'FloatValue';
-export const STRING = 'StringValue';
-export const BOOLEAN = 'BooleanValue';
-export const NULL = 'NullValue';
-export const ENUM = 'EnumValue';
-export const LIST = 'ListValue';
-export const OBJECT = 'ObjectValue';
-export const OBJECT_FIELD = 'ObjectField';
-
-// Directives
-
-export const DIRECTIVE = 'Directive';
-
-// Types
-
-export const NAMED_TYPE = 'NamedType';
-export const LIST_TYPE = 'ListType';
-export const NON_NULL_TYPE = 'NonNullType';
-
-// Type System Definitions
-
-export const SCHEMA_DEFINITION = 'SchemaDefinition';
-export const OPERATION_TYPE_DEFINITION = 'OperationTypeDefinition';
-
-// Type Definitions
-
-export const SCALAR_TYPE_DEFINITION = 'ScalarTypeDefinition';
-export const OBJECT_TYPE_DEFINITION = 'ObjectTypeDefinition';
-export const FIELD_DEFINITION = 'FieldDefinition';
-export const INPUT_VALUE_DEFINITION = 'InputValueDefinition';
-export const INTERFACE_TYPE_DEFINITION = 'InterfaceTypeDefinition';
-export const UNION_TYPE_DEFINITION = 'UnionTypeDefinition';
-export const ENUM_TYPE_DEFINITION = 'EnumTypeDefinition';
-export const ENUM_VALUE_DEFINITION = 'EnumValueDefinition';
-export const INPUT_OBJECT_TYPE_DEFINITION = 'InputObjectTypeDefinition';
-
-// Type Extensions
-
-export const SCALAR_TYPE_EXTENSION = 'ScalarTypeExtension';
-export const OBJECT_TYPE_EXTENSION = 'ObjectTypeExtension';
-export const INTERFACE_TYPE_EXTENSION = 'InterfaceTypeExtension';
-export const UNION_TYPE_EXTENSION = 'UnionTypeExtension';
-export const ENUM_TYPE_EXTENSION = 'EnumTypeExtension';
-export const INPUT_OBJECT_TYPE_EXTENSION = 'InputObjectTypeExtension';
-
-// Directive Definitions
+/**
+ * The set of allowed kind values for AST nodes.
+ */
+export const Kind = Object.freeze({
+  // Name
+  NAME: 'Name',
+
+  // Document
+  DOCUMENT: 'Document',
+  OPERATION_DEFINITION: 'OperationDefinition',
+  VARIABLE_DEFINITION: 'VariableDefinition',
+  VARIABLE: 'Variable',
+  SELECTION_SET: 'SelectionSet',
+  FIELD: 'Field',
+  ARGUMENT: 'Argument',
+
+  // Fragments
+  FRAGMENT_SPREAD: 'FragmentSpread',
+  INLINE_FRAGMENT: 'InlineFragment',
+  FRAGMENT_DEFINITION: 'FragmentDefinition',
+
+  // Values
+  INT: 'IntValue',
+  FLOAT: 'FloatValue',
+  STRING: 'StringValue',
+  BOOLEAN: 'BooleanValue',
+  NULL: 'NullValue',
+  ENUM: 'EnumValue',
+  LIST: 'ListValue',
+  OBJECT: 'ObjectValue',
+  OBJECT_FIELD: 'ObjectField',
+
+  // Directives
+  DIRECTIVE: 'Directive',
+
+  // Types
+  NAMED_TYPE: 'NamedType',
+  LIST_TYPE: 'ListType',
+  NON_NULL_TYPE: 'NonNullType',
+
+  // Type System Definitions
+  SCHEMA_DEFINITION: 'SchemaDefinition',
+  OPERATION_TYPE_DEFINITION: 'OperationTypeDefinition',
+
+  // Type Definitions
+  SCALAR_TYPE_DEFINITION: 'ScalarTypeDefinition',
+  OBJECT_TYPE_DEFINITION: 'ObjectTypeDefinition',
+  FIELD_DEFINITION: 'FieldDefinition',
+  INPUT_VALUE_DEFINITION: 'InputValueDefinition',
+  INTERFACE_TYPE_DEFINITION: 'InterfaceTypeDefinition',
+  UNION_TYPE_DEFINITION: 'UnionTypeDefinition',
+  ENUM_TYPE_DEFINITION: 'EnumTypeDefinition',
+  ENUM_VALUE_DEFINITION: 'EnumValueDefinition',
+  INPUT_OBJECT_TYPE_DEFINITION: 'InputObjectTypeDefinition',
+
+  // Type Extensions
+  SCALAR_TYPE_EXTENSION: 'ScalarTypeExtension',
+  OBJECT_TYPE_EXTENSION: 'ObjectTypeExtension',
+  INTERFACE_TYPE_EXTENSION: 'InterfaceTypeExtension',
+  UNION_TYPE_EXTENSION: 'UnionTypeExtension',
+  ENUM_TYPE_EXTENSION: 'EnumTypeExtension',
+  INPUT_OBJECT_TYPE_EXTENSION: 'InputObjectTypeExtension',
+
+  // Directive Definitions
+  DIRECTIVE_DEFINITION: 'DirectiveDefinition',
+});
 
-export const DIRECTIVE_DEFINITION = 'DirectiveDefinition';
+/**
+ * The enum type representing the possible kind values of AST nodes.
+ */
+export type KindEnum = $Values<typeof Kind>;