graphql/lib/language/parser.js

A Query Language and Runtime which can target any service.

/**
 *  Copyright (c) 2015, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 */

'use strict';

/**
 * Configuration options to control parser behavior
 */

var _Object$defineProperty = require('babel-runtime/core-js/object/define-property')['default'];

_Object$defineProperty(exports, '__esModule', {
  value: true
});

exports.parse = parse;

var _source = require('./source');

var _error = require('./error');

var _lexer = require('./lexer');

var _kinds = require('./kinds');

/**
 * Given a GraphQL source, parses it into a Document. Throws on error.
 */

function parse(source, options) {
  var sourceObj = source instanceof _source.Source ? source : new _source.Source(source);
  var parser = makeParser(sourceObj, options || {});
  return parseDocument(parser);
}

/**
 * Returns the parser object that is used to store state throughout the
 * process of parsing.
 */
function makeParser(source, options) {
  var _lexToken = (0, _lexer.lex)(source);
  return {
    _lexToken: _lexToken,
    source: source,
    options: options,
    prevEnd: 0,
    token: _lexToken()
  };
}

/**
 * Returns a location object, used to identify the place in
 * the source that created a given parsed object.
 */
function loc(parser, start) {
  if (parser.options.noLocation) {
    return null;
  }
  if (parser.options.noSource) {
    return {
      start: start,
      end: parser.prevEnd
    };
  }
  return {
    start: start,
    end: parser.prevEnd,
    source: parser.source
  };
}

/**
 * Moves the internal parser object to the next lexed token.
 */
function advance(parser) {
  var prevEnd = parser.token.end;
  parser.prevEnd = prevEnd;
  parser.token = parser._lexToken(prevEnd);
}

/**
 * Determines if the next token is of a given kind
 */
function peek(parser, kind) {
  return parser.token.kind === kind;
}

/**
 * If the next token is of the given kind, return true after advancing
 * the parser. Otherwise, do not change the parser state and return false.
 */
function skip(parser, kind) {
  var match = parser.token.kind === kind;
  if (match) {
    advance(parser);
  }
  return match;
}

/**
 * If the next token is of the given kind, return that token after advancing
 * the parser. Otherwise, do not change the parser state and return false.
 */
function expect(parser, kind) {
  var token = parser.token;
  if (token.kind === kind) {
    advance(parser);
    return token;
  }
  throw (0, _error.error)(parser.source, token.start, 'Expected ' + (0, _lexer.getTokenKindDesc)(kind) + ', found ' + (0, _lexer.getTokenDesc)(token));
}

/**
 * If the next token is a keyword with the given value, return that token after
 * advancing the parser. Otherwise, do not change the parser state and return
 * false.
 */
function expectKeyword(parser, value) {
  var token = parser.token;
  if (token.kind === _lexer.TokenKind.NAME && token.value === value) {
    advance(parser);
    return token;
  }
  throw (0, _error.error)(parser.source, token.start, 'Expected "' + value + '", found ' + (0, _lexer.getTokenDesc)(token));
}

/**
 * Helper function for creating an error when an unexpected lexed token
 * is encountered.
 */
function unexpected(parser, atToken) {
  var token = atToken || parser.token;
  return (0, _error.error)(parser.source, token.start, 'Unexpected ' + (0, _lexer.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.
 */
function any(parser, openKind, parseFn, closeKind) {
  expect(parser, openKind);
  var nodes = [];
  while (!skip(parser, closeKind)) {
    nodes.push(parseFn(parser));
  }
  return nodes;
}

/**
 * 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.
 */
function many(parser, openKind, parseFn, closeKind) {
  expect(parser, openKind);
  var nodes = [parseFn(parser)];
  while (!skip(parser, closeKind)) {
    nodes.push(parseFn(parser));
  }
  return nodes;
}

/**
 * Converts a name lex token into a name parse node.
 */
function parseName(parser) {
  var token = expect(parser, _lexer.TokenKind.NAME);
  return {
    kind: _kinds.NAME,
    value: token.value,
    loc: loc(parser, token.start)
  };
}

// Implements the parsing rules in the Document section.

function parseDocument(parser) {
  var start = parser.token.start;
  var definitions = [];
  do {
    if (peek(parser, _lexer.TokenKind.BRACE_L)) {
      definitions.push(parseOperationDefinition(parser));
    } else if (peek(parser, _lexer.TokenKind.NAME)) {
      if (parser.token.value === 'query' || parser.token.value === 'mutation') {
        definitions.push(parseOperationDefinition(parser));
      } else if (parser.token.value === 'fragment') {
        definitions.push(parseFragmentDefinition(parser));
      } else {
        throw unexpected(parser);
      }
    } else {
      throw unexpected(parser);
    }
  } while (!skip(parser, _lexer.TokenKind.EOF));
  return {
    kind: _kinds.DOCUMENT,
    definitions: definitions,
    loc: loc(parser, start)
  };
}

// Implements the parsing rules in the Operations section.

function parseOperationDefinition(parser) {
  var start = parser.token.start;
  if (peek(parser, _lexer.TokenKind.BRACE_L)) {
    return {
      kind: _kinds.OPERATION_DEFINITION,
      operation: 'query',
      name: null,
      variableDefinitions: null,
      directives: [],
      selectionSet: parseSelectionSet(parser),
      loc: loc(parser, start)
    };
  }
  var operationToken = expect(parser, _lexer.TokenKind.NAME);
  var operation = operationToken.value;
  return {
    kind: _kinds.OPERATION_DEFINITION,
    operation: operation,
    name: parseName(parser),
    variableDefinitions: parseVariableDefinitions(parser),
    directives: parseDirectives(parser),
    selectionSet: parseSelectionSet(parser),
    loc: loc(parser, start)
  };
}

function parseVariableDefinitions(parser) {
  return peek(parser, _lexer.TokenKind.PAREN_L) ? many(parser, _lexer.TokenKind.PAREN_L, parseVariableDefinition, _lexer.TokenKind.PAREN_R) : [];
}

function parseVariableDefinition(parser) {
  var start = parser.token.start;
  return {
    kind: _kinds.VARIABLE_DEFINITION,
    variable: parseVariable(parser),
    type: (expect(parser, _lexer.TokenKind.COLON), parseType(parser)),
    defaultValue: skip(parser, _lexer.TokenKind.EQUALS) ? parseValue(parser, true) : null,
    loc: loc(parser, start)
  };
}

function parseVariable(parser) {
  var start = parser.token.start;
  expect(parser, _lexer.TokenKind.DOLLAR);
  return {
    kind: _kinds.VARIABLE,
    name: parseName(parser),
    loc: loc(parser, start)
  };
}

function parseSelectionSet(parser) {
  var start = parser.token.start;
  return {
    kind: _kinds.SELECTION_SET,
    selections: many(parser, _lexer.TokenKind.BRACE_L, parseSelection, _lexer.TokenKind.BRACE_R),
    loc: loc(parser, start)
  };
}

function parseSelection(parser) {
  return peek(parser, _lexer.TokenKind.SPREAD) ? parseFragment(parser) : parseField(parser);
}

/**
 * Corresponds to both Field and Alias in the spec
 */
function parseField(parser) {
  var start = parser.token.start;

  var nameOrAlias = parseName(parser);
  var alias;
  var name;
  if (skip(parser, _lexer.TokenKind.COLON)) {
    alias = nameOrAlias;
    name = parseName(parser);
  } else {
    alias = null;
    name = nameOrAlias;
  }

  return {
    kind: _kinds.FIELD,
    alias: alias,
    name: name,
    arguments: parseArguments(parser),
    directives: parseDirectives(parser),
    selectionSet: peek(parser, _lexer.TokenKind.BRACE_L) ? parseSelectionSet(parser) : null,
    loc: loc(parser, start)
  };
}

function parseArguments(parser) {
  return peek(parser, _lexer.TokenKind.PAREN_L) ? many(parser, _lexer.TokenKind.PAREN_L, parseArgument, _lexer.TokenKind.PAREN_R) : [];
}

function parseArgument(parser) {
  var start = parser.token.start;
  return {
    kind: _kinds.ARGUMENT,
    name: parseName(parser),
    value: (expect(parser, _lexer.TokenKind.COLON), parseValue(parser, false)),
    loc: loc(parser, start)
  };
}

// Implements the parsing rules in the Fragments section.

/**
 * Corresponds to both FragmentSpread and InlineFragment in the spec
 */
function parseFragment(parser) {
  var start = parser.token.start;
  expect(parser, _lexer.TokenKind.SPREAD);
  if (parser.token.value === 'on') {
    advance(parser);
    return {
      kind: _kinds.INLINE_FRAGMENT,
      typeCondition: parseName(parser),
      directives: parseDirectives(parser),
      selectionSet: parseSelectionSet(parser),
      loc: loc(parser, start)
    };
  }
  return {
    kind: _kinds.FRAGMENT_SPREAD,
    name: parseName(parser),
    directives: parseDirectives(parser),
    loc: loc(parser, start)
  };
}

function parseFragmentDefinition(parser) {
  var start = parser.token.start;
  expectKeyword(parser, 'fragment');
  return {
    kind: _kinds.FRAGMENT_DEFINITION,
    name: parseName(parser),
    typeCondition: (expectKeyword(parser, 'on'), parseName(parser)),
    directives: parseDirectives(parser),
    selectionSet: parseSelectionSet(parser),
    loc: loc(parser, start)
  };
}

// Implements the parsing rules in the Values section.

function parseVariableValue(parser) {
  return parseValue(parser, false);
}

function parseConstValue(parser) {
  return parseValue(parser, true);
}

function parseValue(parser, isConst) {
  var token = parser.token;
  switch (token.kind) {
    case _lexer.TokenKind.BRACKET_L:
      return parseArray(parser, isConst);
    case _lexer.TokenKind.BRACE_L:
      return parseObject(parser, isConst);
    case _lexer.TokenKind.INT:
      advance(parser);
      return {
        kind: _kinds.INT,
        value: token.value,
        loc: loc(parser, token.start)
      };
    case _lexer.TokenKind.FLOAT:
      advance(parser);
      return {
        kind: _kinds.FLOAT,
        value: token.value,
        loc: loc(parser, token.start)
      };
    case _lexer.TokenKind.STRING:
      advance(parser);
      return {
        kind: _kinds.STRING,
        value: token.value,
        loc: loc(parser, token.start)
      };
    case _lexer.TokenKind.NAME:
      advance(parser);
      switch (token.value) {
        case 'true':
        case 'false':
          return {
            kind: _kinds.BOOLEAN,
            value: token.value === 'true',
            loc: loc(parser, token.start)
          };
      }
      return {
        kind: _kinds.ENUM,
        value: token.value,
        loc: loc(parser, token.start)
      };
    case _lexer.TokenKind.DOLLAR:
      if (!isConst) {
        return parseVariable(parser);
      }
      break;
  }
  throw unexpected(parser);
}

function parseArray(parser, isConst) {
  var start = parser.token.start;
  var item = isConst ? parseConstValue : parseVariableValue;
  return {
    kind: _kinds.ARRAY,
    values: any(parser, _lexer.TokenKind.BRACKET_L, item, _lexer.TokenKind.BRACKET_R),
    loc: loc(parser, start)
  };
}

function parseObject(parser, isConst) {
  var start = parser.token.start;
  expect(parser, _lexer.TokenKind.BRACE_L);
  var fieldNames = {};
  var fields = [];
  while (!skip(parser, _lexer.TokenKind.BRACE_R)) {
    fields.push(parseObjectField(parser, isConst, fieldNames));
  }
  return {
    kind: _kinds.OBJECT,
    fields: fields,
    loc: loc(parser, start)
  };
}

function parseObjectField(parser, isConst, fieldNames) {
  var start = parser.token.start;
  var name = parseName(parser);
  if (fieldNames.hasOwnProperty(name.value)) {
    throw (0, _error.error)(parser.source, start, 'Duplicate input object field ' + name.value + '.');
  }
  fieldNames[name.value] = true;
  return {
    kind: _kinds.OBJECT_FIELD,
    name: name,
    value: (expect(parser, _lexer.TokenKind.COLON), parseValue(parser, isConst)),
    loc: loc(parser, start)
  };
}

// Implements the parsing rules in the Directives section.

function parseDirectives(parser) {
  var directives = [];
  while (peek(parser, _lexer.TokenKind.AT)) {
    directives.push(parseDirective(parser));
  }
  return directives;
}

function parseDirective(parser) {
  var start = parser.token.start;
  expect(parser, _lexer.TokenKind.AT);
  return {
    kind: _kinds.DIRECTIVE,
    name: parseName(parser),
    value: skip(parser, _lexer.TokenKind.COLON) ? parseValue(parser, false) : null,
    loc: loc(parser, start)
  };
}

// Implements the parsing rules in the Types section.

/**
 * Handles the Type: TypeName, ListType, and NonNullType parsing rules.
 */
function parseType(parser) {
  var start = parser.token.start;
  var type;
  if (skip(parser, _lexer.TokenKind.BRACKET_L)) {
    type = parseType(parser);
    expect(parser, _lexer.TokenKind.BRACKET_R);
    type = {
      kind: _kinds.LIST_TYPE,
      type: type,
      loc: loc(parser, start)
    };
  } else {
    type = parseName(parser);
  }
  if (skip(parser, _lexer.TokenKind.BANG)) {
    return {
      kind: _kinds.NON_NULL_TYPE,
      type: type,
      loc: loc(parser, start)
    };
  }
  return type;
}

/**
 * By default, the parser creates AST nodes that know the location
 * in the source that they correspond to. This configuration flag
 * disables that behavior for performance or testing.
 */

/**
 * By default, the parser creates AST nodes that contain a reference
 * to the source that they were created from. This configuration flag
 * disables that behavior for performance or testing.
 */