graphql/language/parser.mjs

import inspect from '../jsutils/inspect';
import devAssert from '../jsutils/devAssert';
import defineToJSON from '../jsutils/defineToJSON';
import { syntaxError } from '../error/syntaxError';
import { Kind } from './kinds';
import { Source } from './source';
import { createLexer } from './lexer';
import { DirectiveLocation } from './directiveLocation';
import { TokenKind } from './tokenKind';

/**
 * Given a GraphQL source, parses it into a Document.
 * Throws GraphQLError if a syntax error is encountered.
 */
export function parse(source, options) {
  var parser = new Parser(source, options);
  return parser.parseDocument();
}
/**
 * Given a string containing a GraphQL value (ex. `[42]`), parse the AST for
 * that value.
 * Throws GraphQLError if a syntax error is encountered.
 *
 * This is useful within tools that operate upon GraphQL Values directly and
 * in isolation of complete GraphQL documents.
 *
 * Consider providing the results to the utility function: valueFromAST().
 */

export function parseValue(source, options) {
  var parser = new Parser(source, options);
  parser.expectToken(TokenKind.SOF);
  var value = parser.parseValueLiteral(false);
  parser.expectToken(TokenKind.EOF);
  return value;
}
/**
 * Given a string containing a GraphQL Type (ex. `[Int!]`), parse the AST for
 * that type.
 * Throws GraphQLError if a syntax error is encountered.
 *
 * This is useful within tools that operate upon GraphQL Types directly and
 * in isolation of complete GraphQL documents.
 *
 * Consider providing the results to the utility function: typeFromAST().
 */

export function parseType(source, options) {
  var parser = new Parser(source, options);
  parser.expectToken(TokenKind.SOF);
  var type = parser.parseTypeReference();
  parser.expectToken(TokenKind.EOF);
  return type;
}

var Parser =
/*#__PURE__*/
function () {
  function Parser(source, options) {
    var sourceObj = typeof source === 'string' ? new Source(source) : source;
    sourceObj instanceof Source || devAssert(0, "Must provide Source. Received: ".concat(inspect(sourceObj)));
    this._lexer = createLexer(sourceObj);
    this._options = options || {};
  }
  /**
   * Converts a name lex token into a name parse node.
   */


  var _proto = Parser.prototype;

  _proto.parseName = function parseName() {
    var token = this.expectToken(TokenKind.NAME);
    return {
      kind: Kind.NAME,
      value: token.value,
      loc: this.loc(token)
    };
  } // Implements the parsing rules in the Document section.

  /**
   * Document : Definition+
   */
  ;

  _proto.parseDocument = function parseDocument() {
    var start = this._lexer.token;
    return {
      kind: Kind.DOCUMENT,
      definitions: this.many(TokenKind.SOF, this.parseDefinition, TokenKind.EOF),
      loc: this.loc(start)
    };
  }
  /**
   * Definition :
   *   - ExecutableDefinition
   *   - TypeSystemDefinition
   *   - TypeSystemExtension
   *
   * ExecutableDefinition :
   *   - OperationDefinition
   *   - FragmentDefinition
   */
  ;

  _proto.parseDefinition = function parseDefinition() {
    if (this.peek(TokenKind.NAME)) {
      switch (this._lexer.token.value) {
        case 'query':
        case 'mutation':
        case 'subscription':
          return this.parseOperationDefinition();

        case 'fragment':
          return this.parseFragmentDefinition();

        case 'schema':
        case 'scalar':
        case 'type':
        case 'interface':
        case 'union':
        case 'enum':
        case 'input':
        case 'directive':
          return this.parseTypeSystemDefinition();

        case 'extend':
          return this.parseTypeSystemExtension();
      }
    } else if (this.peek(TokenKind.BRACE_L)) {
      return this.parseOperationDefinition();
    } else if (this.peekDescription()) {
      return this.parseTypeSystemDefinition();
    }

    throw this.unexpected();
  } // Implements the parsing rules in the Operations section.

  /**
   * OperationDefinition :
   *  - SelectionSet
   *  - OperationType Name? VariableDefinitions? Directives? SelectionSet
   */
  ;

  _proto.parseOperationDefinition = function parseOperationDefinition() {
    var start = this._lexer.token;

    if (this.peek(TokenKind.BRACE_L)) {
      return {
        kind: Kind.OPERATION_DEFINITION,
        operation: 'query',
        name: undefined,
        variableDefinitions: [],
        directives: [],
        selectionSet: this.parseSelectionSet(),
        loc: this.loc(start)
      };
    }

    var operation = this.parseOperationType();
    var name;

    if (this.peek(TokenKind.NAME)) {
      name = this.parseName();
    }

    return {
      kind: Kind.OPERATION_DEFINITION,
      operation: operation,
      name: name,
      variableDefinitions: this.parseVariableDefinitions(),
      directives: this.parseDirectives(false),
      selectionSet: this.parseSelectionSet(),
      loc: this.loc(start)
    };
  }
  /**
   * OperationType : one of query mutation subscription
   */
  ;

  _proto.parseOperationType = function parseOperationType() {
    var operationToken = this.expectToken(TokenKind.NAME);

    switch (operationToken.value) {
      case 'query':
        return 'query';

      case 'mutation':
        return 'mutation';

      case 'subscription':
        return 'subscription';
    }

    throw this.unexpected(operationToken);
  }
  /**
   * VariableDefinitions : ( VariableDefinition+ )
   */
  ;

  _proto.parseVariableDefinitions = function parseVariableDefinitions() {
    return this.optionalMany(TokenKind.PAREN_L, this.parseVariableDefinition, TokenKind.PAREN_R);
  }
  /**
   * VariableDefinition : Variable : Type DefaultValue? Directives[Const]?
   */
  ;

  _proto.parseVariableDefinition = function parseVariableDefinition() {
    var start = this._lexer.token;
    return {
      kind: Kind.VARIABLE_DEFINITION,
      variable: this.parseVariable(),
      type: (this.expectToken(TokenKind.COLON), this.parseTypeReference()),
      defaultValue: this.expectOptionalToken(TokenKind.EQUALS) ? this.parseValueLiteral(true) : undefined,
      directives: this.parseDirectives(true),
      loc: this.loc(start)
    };
  }
  /**
   * Variable : $ Name
   */
  ;

  _proto.parseVariable = function parseVariable() {
    var start = this._lexer.token;
    this.expectToken(TokenKind.DOLLAR);
    return {
      kind: Kind.VARIABLE,
      name: this.parseName(),
      loc: this.loc(start)
    };
  }
  /**
   * SelectionSet : { Selection+ }
   */
  ;

  _proto.parseSelectionSet = function parseSelectionSet() {
    var start = this._lexer.token;
    return {
      kind: Kind.SELECTION_SET,
      selections: this.many(TokenKind.BRACE_L, this.parseSelection, TokenKind.BRACE_R),
      loc: this.loc(start)
    };
  }
  /**
   * Selection :
   *   - Field
   *   - FragmentSpread
   *   - InlineFragment
   */
  ;

  _proto.parseSelection = function parseSelection() {
    return this.peek(TokenKind.SPREAD) ? this.parseFragment() : this.parseField();
  }
  /**
   * Field : Alias? Name Arguments? Directives? SelectionSet?
   *
   * Alias : Name :
   */
  ;

  _proto.parseField = function parseField() {
    var start = this._lexer.token;
    var nameOrAlias = this.parseName();
    var alias;
    var name;

    if (this.expectOptionalToken(TokenKind.COLON)) {
      alias = nameOrAlias;
      name = this.parseName();
    } else {
      name = nameOrAlias;
    }

    return {
      kind: Kind.FIELD,
      alias: alias,
      name: name,
      arguments: this.parseArguments(false),
      directives: this.parseDirectives(false),
      selectionSet: this.peek(TokenKind.BRACE_L) ? this.parseSelectionSet() : undefined,
      loc: this.loc(start)
    };
  }
  /**
   * Arguments[Const] : ( Argument[?Const]+ )
   */
  ;

  _proto.parseArguments = function parseArguments(isConst) {
    var item = isConst ? this.parseConstArgument : this.parseArgument;
    return this.optionalMany(TokenKind.PAREN_L, item, TokenKind.PAREN_R);
  }
  /**
   * Argument[Const] : Name : Value[?Const]
   */
  ;

  _proto.parseArgument = function parseArgument() {
    var start = this._lexer.token;
    var name = this.parseName();
    this.expectToken(TokenKind.COLON);
    return {
      kind: Kind.ARGUMENT,
      name: name,
      value: this.parseValueLiteral(false),
      loc: this.loc(start)
    };
  };

  _proto.parseConstArgument = function parseConstArgument() {
    var start = this._lexer.token;
    return {
      kind: Kind.ARGUMENT,
      name: this.parseName(),
      value: (this.expectToken(TokenKind.COLON), this.parseValueLiteral(true)),
      loc: this.loc(start)
    };
  } // Implements the parsing rules in the Fragments section.

  /**
   * Corresponds to both FragmentSpread and InlineFragment in the spec.
   *
   * FragmentSpread : ... FragmentName Directives?
   *
   * InlineFragment : ... TypeCondition? Directives? SelectionSet
   */
  ;

  _proto.parseFragment = function parseFragment() {
    var start = this._lexer.token;
    this.expectToken(TokenKind.SPREAD);
    var hasTypeCondition = this.expectOptionalKeyword('on');

    if (!hasTypeCondition && this.peek(TokenKind.NAME)) {
      return {
        kind: Kind.FRAGMENT_SPREAD,
        name: this.parseFragmentName(),
        directives: this.parseDirectives(false),
        loc: this.loc(start)
      };
    }

    return {
      kind: Kind.INLINE_FRAGMENT,
      typeCondition: hasTypeCondition ? this.parseNamedType() : undefined,
      directives: this.parseDirectives(false),
      selectionSet: this.parseSelectionSet(),
      loc: this.loc(start)
    };
  }
  /**
   * FragmentDefinition :
   *   - fragment FragmentName on TypeCondition Directives? SelectionSet
   *
   * TypeCondition : NamedType
   */
  ;

  _proto.parseFragmentDefinition = function parseFragmentDefinition() {
    var start = this._lexer.token;
    this.expectKeyword('fragment'); // Experimental support for defining variables within fragments changes
    // the grammar of FragmentDefinition:
    //   - fragment FragmentName VariableDefinitions? on TypeCondition Directives? SelectionSet

    if (this._options.experimentalFragmentVariables) {
      return {
        kind: Kind.FRAGMENT_DEFINITION,
        name: this.parseFragmentName(),
        variableDefinitions: this.parseVariableDefinitions(),
        typeCondition: (this.expectKeyword('on'), this.parseNamedType()),
        directives: this.parseDirectives(false),
        selectionSet: this.parseSelectionSet(),
        loc: this.loc(start)
      };
    }

    return {
      kind: Kind.FRAGMENT_DEFINITION,
      name: this.parseFragmentName(),
      typeCondition: (this.expectKeyword('on'), this.parseNamedType()),
      directives: this.parseDirectives(false),
      selectionSet: this.parseSelectionSet(),
      loc: this.loc(start)
    };
  }
  /**
   * FragmentName : Name but not `on`
   */
  ;

  _proto.parseFragmentName = function parseFragmentName() {
    if (this._lexer.token.value === 'on') {
      throw this.unexpected();
    }

    return this.parseName();
  } // Implements the parsing rules in the Values section.

  /**
   * Value[Const] :
   *   - [~Const] Variable
   *   - IntValue
   *   - FloatValue
   *   - StringValue
   *   - BooleanValue
   *   - NullValue
   *   - EnumValue
   *   - ListValue[?Const]
   *   - ObjectValue[?Const]
   *
   * BooleanValue : one of `true` `false`
   *
   * NullValue : `null`
   *
   * EnumValue : Name but not `true`, `false` or `null`
   */
  ;

  _proto.parseValueLiteral = function parseValueLiteral(isConst) {
    var token = this._lexer.token;

    switch (token.kind) {
      case TokenKind.BRACKET_L:
        return this.parseList(isConst);

      case TokenKind.BRACE_L:
        return this.parseObject(isConst);

      case TokenKind.INT:
        this._lexer.advance();

        return {
          kind: Kind.INT,
          value: token.value,
          loc: this.loc(token)
        };

      case TokenKind.FLOAT:
        this._lexer.advance();

        return {
          kind: Kind.FLOAT,
          value: token.value,
          loc: this.loc(token)
        };

      case TokenKind.STRING:
      case TokenKind.BLOCK_STRING:
        return this.parseStringLiteral();

      case TokenKind.NAME:
        if (token.value === 'true' || token.value === 'false') {
          this._lexer.advance();

          return {
            kind: Kind.BOOLEAN,
            value: token.value === 'true',
            loc: this.loc(token)
          };
        } else if (token.value === 'null') {
          this._lexer.advance();

          return {
            kind: Kind.NULL,
            loc: this.loc(token)
          };
        }

        this._lexer.advance();

        return {
          kind: Kind.ENUM,
          value: token.value,
          loc: this.loc(token)
        };

      case TokenKind.DOLLAR:
        if (!isConst) {
          return this.parseVariable();
        }

        break;
    }

    throw this.unexpected();
  };

  _proto.parseStringLiteral = function parseStringLiteral() {
    var token = this._lexer.token;

    this._lexer.advance();

    return {
      kind: Kind.STRING,
      value: token.value,
      block: token.kind === TokenKind.BLOCK_STRING,
      loc: this.loc(token)
    };
  }
  /**
   * ListValue[Const] :
   *   - [ ]
   *   - [ Value[?Const]+ ]
   */
  ;

  _proto.parseList = function parseList(isConst) {
    var _this = this;

    var start = this._lexer.token;

    var item = function item() {
      return _this.parseValueLiteral(isConst);
    };

    return {
      kind: Kind.LIST,
      values: this.any(TokenKind.BRACKET_L, item, TokenKind.BRACKET_R),
      loc: this.loc(start)
    };
  }
  /**
   * ObjectValue[Const] :
   *   - { }
   *   - { ObjectField[?Const]+ }
   */
  ;

  _proto.parseObject = function parseObject(isConst) {
    var _this2 = this;

    var start = this._lexer.token;

    var item = function item() {
      return _this2.parseObjectField(isConst);
    };

    return {
      kind: Kind.OBJECT,
      fields: this.any(TokenKind.BRACE_L, item, TokenKind.BRACE_R),
      loc: this.loc(start)
    };
  }
  /**
   * ObjectField[Const] : Name : Value[?Const]
   */
  ;

  _proto.parseObjectField = function parseObjectField(isConst) {
    var start = this._lexer.token;
    var name = this.parseName();
    this.expectToken(TokenKind.COLON);
    return {
      kind: Kind.OBJECT_FIELD,
      name: name,
      value: this.parseValueLiteral(isConst),
      loc: this.loc(start)
    };
  } // Implements the parsing rules in the Directives section.

  /**
   * Directives[Const] : Directive[?Const]+
   */
  ;

  _proto.parseDirectives = function parseDirectives(isConst) {
    var directives = [];

    while (this.peek(TokenKind.AT)) {
      directives.push(this.parseDirective(isConst));
    }

    return directives;
  }
  /**
   * Directive[Const] : @ Name Arguments[?Const]?
   */
  ;

  _proto.parseDirective = function parseDirective(isConst) {
    var start = this._lexer.token;
    this.expectToken(TokenKind.AT);
    return {
      kind: Kind.DIRECTIVE,
      name: this.parseName(),
      arguments: this.parseArguments(isConst),
      loc: this.loc(start)
    };
  } // Implements the parsing rules in the Types section.

  /**
   * Type :
   *   - NamedType
   *   - ListType
   *   - NonNullType
   */
  ;

  _proto.parseTypeReference = function parseTypeReference() {
    var start = this._lexer.token;
    var type;

    if (this.expectOptionalToken(TokenKind.BRACKET_L)) {
      type = this.parseTypeReference();
      this.expectToken(TokenKind.BRACKET_R);
      type = {
        kind: Kind.LIST_TYPE,
        type: type,
        loc: this.loc(start)
      };
    } else {
      type = this.parseNamedType();
    }

    if (this.expectOptionalToken(TokenKind.BANG)) {
      return {
        kind: Kind.NON_NULL_TYPE,
        type: type,
        loc: this.loc(start)
      };
    }

    return type;
  }
  /**
   * NamedType : Name
   */
  ;

  _proto.parseNamedType = function parseNamedType() {
    var start = this._lexer.token;
    return {
      kind: Kind.NAMED_TYPE,
      name: this.parseName(),
      loc: this.loc(start)
    };
  } // Implements the parsing rules in the Type Definition section.

  /**
   * TypeSystemDefinition :
   *   - SchemaDefinition
   *   - TypeDefinition
   *   - DirectiveDefinition
   *
   * TypeDefinition :
   *   - ScalarTypeDefinition
   *   - ObjectTypeDefinition
   *   - InterfaceTypeDefinition
   *   - UnionTypeDefinition
   *   - EnumTypeDefinition
   *   - InputObjectTypeDefinition
   */
  ;

  _proto.parseTypeSystemDefinition = function parseTypeSystemDefinition() {
    // Many definitions begin with a description and require a lookahead.
    var keywordToken = this.peekDescription() ? this._lexer.lookahead() : this._lexer.token;

    if (keywordToken.kind === TokenKind.NAME) {
      switch (keywordToken.value) {
        case 'schema':
          return this.parseSchemaDefinition();

        case 'scalar':
          return this.parseScalarTypeDefinition();

        case 'type':
          return this.parseObjectTypeDefinition();

        case 'interface':
          return this.parseInterfaceTypeDefinition();

        case 'union':
          return this.parseUnionTypeDefinition();

        case 'enum':
          return this.parseEnumTypeDefinition();

        case 'input':
          return this.parseInputObjectTypeDefinition();

        case 'directive':
          return this.parseDirectiveDefinition();
      }
    }

    throw this.unexpected(keywordToken);
  };

  _proto.peekDescription = function peekDescription() {
    return this.peek(TokenKind.STRING) || this.peek(TokenKind.BLOCK_STRING);
  }
  /**
   * Description : StringValue
   */
  ;

  _proto.parseDescription = function parseDescription() {
    if (this.peekDescription()) {
      return this.parseStringLiteral();
    }
  }
  /**
   * SchemaDefinition : schema Directives[Const]? { OperationTypeDefinition+ }
   */
  ;

  _proto.parseSchemaDefinition = function parseSchemaDefinition() {
    var start = this._lexer.token;
    this.expectKeyword('schema');
    var directives = this.parseDirectives(true);
    var operationTypes = this.many(TokenKind.BRACE_L, this.parseOperationTypeDefinition, TokenKind.BRACE_R);
    return {
      kind: Kind.SCHEMA_DEFINITION,
      directives: directives,
      operationTypes: operationTypes,
      loc: this.loc(start)
    };
  }
  /**
   * OperationTypeDefinition : OperationType : NamedType
   */
  ;

  _proto.parseOperationTypeDefinition = function parseOperationTypeDefinition() {
    var start = this._lexer.token;
    var operation = this.parseOperationType();
    this.expectToken(TokenKind.COLON);
    var type = this.parseNamedType();
    return {
      kind: Kind.OPERATION_TYPE_DEFINITION,
      operation: operation,
      type: type,
      loc: this.loc(start)
    };
  }
  /**
   * ScalarTypeDefinition : Description? scalar Name Directives[Const]?
   */
  ;

  _proto.parseScalarTypeDefinition = function parseScalarTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('scalar');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    return {
      kind: Kind.SCALAR_TYPE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      loc: this.loc(start)
    };
  }
  /**
   * ObjectTypeDefinition :
   *   Description?
   *   type Name ImplementsInterfaces? Directives[Const]? FieldsDefinition?
   */
  ;

  _proto.parseObjectTypeDefinition = function parseObjectTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('type');
    var name = this.parseName();
    var interfaces = this.parseImplementsInterfaces();
    var directives = this.parseDirectives(true);
    var fields = this.parseFieldsDefinition();
    return {
      kind: Kind.OBJECT_TYPE_DEFINITION,
      description: description,
      name: name,
      interfaces: interfaces,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * ImplementsInterfaces :
   *   - implements `&`? NamedType
   *   - ImplementsInterfaces & NamedType
   */
  ;

  _proto.parseImplementsInterfaces = function parseImplementsInterfaces() {
    var types = [];

    if (this.expectOptionalKeyword('implements')) {
      // Optional leading ampersand
      this.expectOptionalToken(TokenKind.AMP);

      do {
        types.push(this.parseNamedType());
      } while (this.expectOptionalToken(TokenKind.AMP) || // Legacy support for the SDL?
      this._options.allowLegacySDLImplementsInterfaces && this.peek(TokenKind.NAME));
    }

    return types;
  }
  /**
   * FieldsDefinition : { FieldDefinition+ }
   */
  ;

  _proto.parseFieldsDefinition = function parseFieldsDefinition() {
    // Legacy support for the SDL?
    if (this._options.allowLegacySDLEmptyFields && this.peek(TokenKind.BRACE_L) && this._lexer.lookahead().kind === TokenKind.BRACE_R) {
      this._lexer.advance();

      this._lexer.advance();

      return [];
    }

    return this.optionalMany(TokenKind.BRACE_L, this.parseFieldDefinition, TokenKind.BRACE_R);
  }
  /**
   * FieldDefinition :
   *   - Description? Name ArgumentsDefinition? : Type Directives[Const]?
   */
  ;

  _proto.parseFieldDefinition = function parseFieldDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    var name = this.parseName();
    var args = this.parseArgumentDefs();
    this.expectToken(TokenKind.COLON);
    var type = this.parseTypeReference();
    var directives = this.parseDirectives(true);
    return {
      kind: Kind.FIELD_DEFINITION,
      description: description,
      name: name,
      arguments: args,
      type: type,
      directives: directives,
      loc: this.loc(start)
    };
  }
  /**
   * ArgumentsDefinition : ( InputValueDefinition+ )
   */
  ;

  _proto.parseArgumentDefs = function parseArgumentDefs() {
    return this.optionalMany(TokenKind.PAREN_L, this.parseInputValueDef, TokenKind.PAREN_R);
  }
  /**
   * InputValueDefinition :
   *   - Description? Name : Type DefaultValue? Directives[Const]?
   */
  ;

  _proto.parseInputValueDef = function parseInputValueDef() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    var name = this.parseName();
    this.expectToken(TokenKind.COLON);
    var type = this.parseTypeReference();
    var defaultValue;

    if (this.expectOptionalToken(TokenKind.EQUALS)) {
      defaultValue = this.parseValueLiteral(true);
    }

    var directives = this.parseDirectives(true);
    return {
      kind: Kind.INPUT_VALUE_DEFINITION,
      description: description,
      name: name,
      type: type,
      defaultValue: defaultValue,
      directives: directives,
      loc: this.loc(start)
    };
  }
  /**
   * InterfaceTypeDefinition :
   *   - Description? interface Name Directives[Const]? FieldsDefinition?
   */
  ;

  _proto.parseInterfaceTypeDefinition = function parseInterfaceTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('interface');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var fields = this.parseFieldsDefinition();
    return {
      kind: Kind.INTERFACE_TYPE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * UnionTypeDefinition :
   *   - Description? union Name Directives[Const]? UnionMemberTypes?
   */
  ;

  _proto.parseUnionTypeDefinition = function parseUnionTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('union');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var types = this.parseUnionMemberTypes();
    return {
      kind: Kind.UNION_TYPE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      types: types,
      loc: this.loc(start)
    };
  }
  /**
   * UnionMemberTypes :
   *   - = `|`? NamedType
   *   - UnionMemberTypes | NamedType
   */
  ;

  _proto.parseUnionMemberTypes = function parseUnionMemberTypes() {
    var types = [];

    if (this.expectOptionalToken(TokenKind.EQUALS)) {
      // Optional leading pipe
      this.expectOptionalToken(TokenKind.PIPE);

      do {
        types.push(this.parseNamedType());
      } while (this.expectOptionalToken(TokenKind.PIPE));
    }

    return types;
  }
  /**
   * EnumTypeDefinition :
   *   - Description? enum Name Directives[Const]? EnumValuesDefinition?
   */
  ;

  _proto.parseEnumTypeDefinition = function parseEnumTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('enum');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var values = this.parseEnumValuesDefinition();
    return {
      kind: Kind.ENUM_TYPE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      values: values,
      loc: this.loc(start)
    };
  }
  /**
   * EnumValuesDefinition : { EnumValueDefinition+ }
   */
  ;

  _proto.parseEnumValuesDefinition = function parseEnumValuesDefinition() {
    return this.optionalMany(TokenKind.BRACE_L, this.parseEnumValueDefinition, TokenKind.BRACE_R);
  }
  /**
   * EnumValueDefinition : Description? EnumValue Directives[Const]?
   *
   * EnumValue : Name
   */
  ;

  _proto.parseEnumValueDefinition = function parseEnumValueDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    return {
      kind: Kind.ENUM_VALUE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      loc: this.loc(start)
    };
  }
  /**
   * InputObjectTypeDefinition :
   *   - Description? input Name Directives[Const]? InputFieldsDefinition?
   */
  ;

  _proto.parseInputObjectTypeDefinition = function parseInputObjectTypeDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('input');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var fields = this.parseInputFieldsDefinition();
    return {
      kind: Kind.INPUT_OBJECT_TYPE_DEFINITION,
      description: description,
      name: name,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * InputFieldsDefinition : { InputValueDefinition+ }
   */
  ;

  _proto.parseInputFieldsDefinition = function parseInputFieldsDefinition() {
    return this.optionalMany(TokenKind.BRACE_L, this.parseInputValueDef, TokenKind.BRACE_R);
  }
  /**
   * TypeSystemExtension :
   *   - SchemaExtension
   *   - TypeExtension
   *
   * TypeExtension :
   *   - ScalarTypeExtension
   *   - ObjectTypeExtension
   *   - InterfaceTypeExtension
   *   - UnionTypeExtension
   *   - EnumTypeExtension
   *   - InputObjectTypeDefinition
   */
  ;

  _proto.parseTypeSystemExtension = function parseTypeSystemExtension() {
    var keywordToken = this._lexer.lookahead();

    if (keywordToken.kind === TokenKind.NAME) {
      switch (keywordToken.value) {
        case 'schema':
          return this.parseSchemaExtension();

        case 'scalar':
          return this.parseScalarTypeExtension();

        case 'type':
          return this.parseObjectTypeExtension();

        case 'interface':
          return this.parseInterfaceTypeExtension();

        case 'union':
          return this.parseUnionTypeExtension();

        case 'enum':
          return this.parseEnumTypeExtension();

        case 'input':
          return this.parseInputObjectTypeExtension();
      }
    }

    throw this.unexpected(keywordToken);
  }
  /**
   * SchemaExtension :
   *  - extend schema Directives[Const]? { OperationTypeDefinition+ }
   *  - extend schema Directives[Const]
   */
  ;

  _proto.parseSchemaExtension = function parseSchemaExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('schema');
    var directives = this.parseDirectives(true);
    var operationTypes = this.optionalMany(TokenKind.BRACE_L, this.parseOperationTypeDefinition, TokenKind.BRACE_R);

    if (directives.length === 0 && operationTypes.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.SCHEMA_EXTENSION,
      directives: directives,
      operationTypes: operationTypes,
      loc: this.loc(start)
    };
  }
  /**
   * ScalarTypeExtension :
   *   - extend scalar Name Directives[Const]
   */
  ;

  _proto.parseScalarTypeExtension = function parseScalarTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('scalar');
    var name = this.parseName();
    var directives = this.parseDirectives(true);

    if (directives.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.SCALAR_TYPE_EXTENSION,
      name: name,
      directives: directives,
      loc: this.loc(start)
    };
  }
  /**
   * ObjectTypeExtension :
   *  - extend type Name ImplementsInterfaces? Directives[Const]? FieldsDefinition
   *  - extend type Name ImplementsInterfaces? Directives[Const]
   *  - extend type Name ImplementsInterfaces
   */
  ;

  _proto.parseObjectTypeExtension = function parseObjectTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('type');
    var name = this.parseName();
    var interfaces = this.parseImplementsInterfaces();
    var directives = this.parseDirectives(true);
    var fields = this.parseFieldsDefinition();

    if (interfaces.length === 0 && directives.length === 0 && fields.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.OBJECT_TYPE_EXTENSION,
      name: name,
      interfaces: interfaces,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * InterfaceTypeExtension :
   *   - extend interface Name Directives[Const]? FieldsDefinition
   *   - extend interface Name Directives[Const]
   */
  ;

  _proto.parseInterfaceTypeExtension = function parseInterfaceTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('interface');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var fields = this.parseFieldsDefinition();

    if (directives.length === 0 && fields.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.INTERFACE_TYPE_EXTENSION,
      name: name,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * UnionTypeExtension :
   *   - extend union Name Directives[Const]? UnionMemberTypes
   *   - extend union Name Directives[Const]
   */
  ;

  _proto.parseUnionTypeExtension = function parseUnionTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('union');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var types = this.parseUnionMemberTypes();

    if (directives.length === 0 && types.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.UNION_TYPE_EXTENSION,
      name: name,
      directives: directives,
      types: types,
      loc: this.loc(start)
    };
  }
  /**
   * EnumTypeExtension :
   *   - extend enum Name Directives[Const]? EnumValuesDefinition
   *   - extend enum Name Directives[Const]
   */
  ;

  _proto.parseEnumTypeExtension = function parseEnumTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('enum');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var values = this.parseEnumValuesDefinition();

    if (directives.length === 0 && values.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.ENUM_TYPE_EXTENSION,
      name: name,
      directives: directives,
      values: values,
      loc: this.loc(start)
    };
  }
  /**
   * InputObjectTypeExtension :
   *   - extend input Name Directives[Const]? InputFieldsDefinition
   *   - extend input Name Directives[Const]
   */
  ;

  _proto.parseInputObjectTypeExtension = function parseInputObjectTypeExtension() {
    var start = this._lexer.token;
    this.expectKeyword('extend');
    this.expectKeyword('input');
    var name = this.parseName();
    var directives = this.parseDirectives(true);
    var fields = this.parseInputFieldsDefinition();

    if (directives.length === 0 && fields.length === 0) {
      throw this.unexpected();
    }

    return {
      kind: Kind.INPUT_OBJECT_TYPE_EXTENSION,
      name: name,
      directives: directives,
      fields: fields,
      loc: this.loc(start)
    };
  }
  /**
   * DirectiveDefinition :
   *   - Description? directive @ Name ArgumentsDefinition? `repeatable`? on DirectiveLocations
   */
  ;

  _proto.parseDirectiveDefinition = function parseDirectiveDefinition() {
    var start = this._lexer.token;
    var description = this.parseDescription();
    this.expectKeyword('directive');
    this.expectToken(TokenKind.AT);
    var name = this.parseName();
    var args = this.parseArgumentDefs();
    var repeatable = this.expectOptionalKeyword('repeatable');
    this.expectKeyword('on');
    var locations = this.parseDirectiveLocations();
    return {
      kind: Kind.DIRECTIVE_DEFINITION,
      description: description,
      name: name,
      arguments: args,
      repeatable: repeatable,
      locations: locations,
      loc: this.loc(start)
    };
  }
  /**
   * DirectiveLocations :
   *   - `|`? DirectiveLocation
   *   - DirectiveLocations | DirectiveLocation
   */
  ;

  _proto.parseDirectiveLocations = function parseDirectiveLocations() {
    // Optional leading pipe
    this.expectOptionalToken(TokenKind.PIPE);
    var locations = [];

    do {
      locations.push(this.parseDirectiveLocation());
    } while (this.expectOptionalToken(TokenKind.PIPE));

    return locations;
  }
  /*
   * DirectiveLocation :
   *   - ExecutableDirectiveLocation
   *   - TypeSystemDirectiveLocation
   *
   * ExecutableDirectiveLocation : one of
   *   `QUERY`
   *   `MUTATION`
   *   `SUBSCRIPTION`
   *   `FIELD`
   *   `FRAGMENT_DEFINITION`
   *   `FRAGMENT_SPREAD`
   *   `INLINE_FRAGMENT`
   *
   * TypeSystemDirectiveLocation : one of
   *   `SCHEMA`
   *   `SCALAR`
   *   `OBJECT`
   *   `FIELD_DEFINITION`
   *   `ARGUMENT_DEFINITION`
   *   `INTERFACE`
   *   `UNION`
   *   `ENUM`
   *   `ENUM_VALUE`
   *   `INPUT_OBJECT`
   *   `INPUT_FIELD_DEFINITION`
   */
  ;

  _proto.parseDirectiveLocation = function parseDirectiveLocation() {
    var start = this._lexer.token;
    var name = this.parseName();

    if (DirectiveLocation[name.value] !== undefined) {
      return name;
    }

    throw this.unexpected(start);
  } // Core parsing utility functions

  /**
   * Returns a location object, used to identify the place in
   * the source that created a given parsed object.
   */
  ;

  _proto.loc = function loc(startToken) {
    if (!this._options.noLocation) {
      return new Loc(startToken, this._lexer.lastToken, this._lexer.source);
    }
  }
  /**
   * Determines if the next token is of a given kind
   */
  ;

  _proto.peek = function peek(kind) {
    return this._lexer.token.kind === kind;
  }
  /**
   * If the next token is of the given kind, return that token after advancing
   * the lexer. Otherwise, do not change the parser state and throw an error.
   */
  ;

  _proto.expectToken = function expectToken(kind) {
    var token = this._lexer.token;

    if (token.kind === kind) {
      this._lexer.advance();

      return token;
    }

    throw syntaxError(this._lexer.source, token.start, "Expected ".concat(kind, ", found ").concat(getTokenDesc(token)));
  }
  /**
   * If the next token is of the given kind, return that token after advancing
   * the lexer. Otherwise, do not change the parser state and return undefined.
   */
  ;

  _proto.expectOptionalToken = function expectOptionalToken(kind) {
    var token = this._lexer.token;

    if (token.kind === kind) {
      this._lexer.advance();

      return token;
    }

    return undefined;
  }
  /**
   * If the next token is a given keyword, advance the lexer.
   * Otherwise, do not change the parser state and throw an error.
   */
  ;

  _proto.expectKeyword = function expectKeyword(value) {
    var token = this._lexer.token;

    if (token.kind === TokenKind.NAME && token.value === value) {
      this._lexer.advance();
    } else {
      throw syntaxError(this._lexer.source, token.start, "Expected \"".concat(value, "\", found ").concat(getTokenDesc(token)));
    }
  }
  /**
   * If the next token is a given keyword, return "true" after advancing
   * the lexer. Otherwise, do not change the parser state and return "false".
   */
  ;

  _proto.expectOptionalKeyword = function expectOptionalKeyword(value) {
    var token = this._lexer.token;

    if (token.kind === TokenKind.NAME && token.value === value) {
      this._lexer.advance();

      return true;
    }

    return false;
  }
  /**
   * Helper function for creating an error when an unexpected lexed token
   * is encountered.
   */
  ;

  _proto.unexpected = function unexpected(atToken) {
    var token = atToken || this._lexer.token;
    return syntaxError(this._lexer.source, token.start, "Unexpected ".concat(getTokenDesc(token)));
  }
  /**
   * Returns a possibly empty list of parse nodes, determined by
   * the parseFn. This list begins with a lex token of openKind
   * and ends with a lex token of closeKind. Advances the parser
   * to the next lex token after the closing token.
   */
  ;

  _proto.any = function any(openKind, parseFn, closeKind) {
    this.expectToken(openKind);
    var nodes = [];

    while (!this.expectOptionalToken(closeKind)) {
      nodes.push(parseFn.call(this));
    }

    return nodes;
  }
  /**
   * Returns a list of parse nodes, determined by the parseFn.
   * It can be empty only if open token is missing otherwise it will always
   * return non-empty list that begins with a lex token of openKind and ends
   * with a lex token of closeKind. Advances the parser to the next lex token
   * after the closing token.
   */
  ;

  _proto.optionalMany = function optionalMany(openKind, parseFn, closeKind) {
    if (this.expectOptionalToken(openKind)) {
      var nodes = [];

      do {
        nodes.push(parseFn.call(this));
      } while (!this.expectOptionalToken(closeKind));

      return nodes;
    }

    return [];
  }
  /**
   * Returns a non-empty list of parse nodes, determined by
   * the parseFn. This list begins with a lex token of openKind
   * and ends with a lex token of closeKind. Advances the parser
   * to the next lex token after the closing token.
   */
  ;

  _proto.many = function many(openKind, parseFn, closeKind) {
    this.expectToken(openKind);
    var nodes = [];

    do {
      nodes.push(parseFn.call(this));
    } while (!this.expectOptionalToken(closeKind));

    return nodes;
  };

  return Parser;
}();

function Loc(startToken, endToken, source) {
  this.start = startToken.start;
  this.end = endToken.end;
  this.startToken = startToken;
  this.endToken = endToken;
  this.source = source;
} // Print a simplified form when appearing in JSON/util.inspect.


defineToJSON(Loc, function () {
  return {
    start: this.start,
    end: this.end
  };
});
/**
 * A helper function to describe a token as a string for debugging
 */

function getTokenDesc(token) {
  var value = token.value;
  return value ? "".concat(token.kind, " \"").concat(value, "\"") : token.kind;
}