graphql/lib/language/error.js

A Query Language and Runtime which can target any service.

/* @flow */
/**
 *  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';

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

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

exports.error = error;

var _location = require('./location');

function error(source, position, description) {
  var location = (0, _location.getLocation)(source, position);
  var syntaxError = new Error('Syntax Error ' + source.name + ' (' + location.line + ':' + location.column + ') ' + description + '\n\n' + highlightSourceAtLocation(source, location));
  syntaxError.source = source;
  syntaxError.position = position;
  syntaxError.location = location;
  return syntaxError;
}

function highlightSourceAtLocation(source, location) {
  var line = location.line;
  var prevLineNum = (line - 1).toString();
  var lineNum = line.toString();
  var nextLineNum = (line + 1).toString();
  var padLen = nextLineNum.length;
  var lines = source.body.split(/\r\n|[\n\r\u2028\u2029]/g);
  return (line >= 2 ? lpad(padLen, prevLineNum) + ': ' + lines[line - 2] + '\n' : '') + lpad(padLen, lineNum) + ': ' + lines[line - 1] + '\n' + Array(2 + padLen + location.column).join(' ') + '^\n' + (line < lines.length ? lpad(padLen, nextLineNum) + ': ' + lines[line] + '\n' : '');
}

function lpad(len, str) {
  return Array(len - str.length + 1).join(' ') + str;
}