How to use the graphql-language-service-parser.CharacterStream function in graphql-language-service-parser

function runOnlineParser(
  queryText: string,
  callback: callbackFnType,
): ContextToken {
  const lines = queryText.split('\n');
  const parser = onlineParser();
  let state = parser.startState();
  let style = '';

  let stream: CharacterStream = new CharacterStream('');

  for (let i = 0; i < lines.length; i++) {
    stream = new CharacterStream(lines[i]);
    // Stop the parsing when the stream arrives at the current cursor position
    while (!stream.eol()) {
      style = parser.token(stream, state);
      const code = callback(stream, state, style, i);
      if (code === 'BREAK') {
        break;
      }
    }

    if (!state.kind) {
      state = parser.startState();
    }
  }

  return {
    start: stream.getStartOfToken(),

function runOnlineParser(
  queryText: string,
  callback: callbackFnType,
): ContextToken {
  const lines = queryText.split('\n');
  const parser = onlineParser();
  let state = parser.startState();
  let style = '';

  let stream: CharacterStream = new CharacterStream('');

  for (let i = 0; i < lines.length; i++) {
    stream = new CharacterStream(lines[i]);
    while (!stream.eol()) {
      style = parser.token(stream, state);
      const code = callback(stream, state, style, i);
      if (code === 'BREAK') {
        break;
      }
    }

    // Above while loop won't run if there is an empty line.
    // Run the callback one more time to catch this.
    callback(stream, state, style, i);

    if (!state.kind) {

function runOnlineParser(
  queryText: string,
  callback: callbackFnType,
): ContextToken {
  const lines = queryText.split('\n');
  const parser = onlineParser();
  let state = parser.startState();
  let style = '';

  let stream: CharacterStream = new CharacterStream('');

  for (let i = 0; i < lines.length; i++) {
    stream = new CharacterStream(lines[i]);
    // Stop the parsing when the stream arrives at the current cursor position
    while (!stream.eol()) {
      style = parser.token(stream, state);
      const code = callback(stream, state, style, i);
      if (code === 'BREAK') {
        break;
      }
    }

    if (!state.kind) {
      state = parser.startState();
    }
  }

function runOnlineParser(
  queryText: string,
  callback: callbackFnType,
): ContextToken {
  const lines = queryText.split('\n');
  const parser = onlineParser();
  let state = parser.startState();
  let style = '';

  let stream: CharacterStream = new CharacterStream('');

  for (let i = 0; i < lines.length; i++) {
    stream = new CharacterStream(lines[i]);
    while (!stream.eol()) {
      style = parser.token(stream, state);
      const code = callback(stream, state, style, i);
      if (code === 'BREAK') {
        break;
      }
    }

    // Above while loop won't run if there is an empty line.
    // Run the callback one more time to catch this.
    callback(stream, state, style, i);

    if (!state.kind) {
      state = parser.startState();
    }
  }

function getRange(location: GraphQLErrorLocation, queryText: string) {
  const parser = onlineParser();
  const state = parser.startState();
  const lines = queryText.split('\n');

  invariant(
    lines.length >= location.line,
    'Query text must have more lines than where the error happened',
  );

  let stream = null;

  for (let i = 0; i < location.line; i++) {
    stream = new CharacterStream(lines[i]);
    while (!stream.eol()) {
      const style = parser.token(stream, state);
      if (style === 'invalidchar') {
        break;
      }
    }
  }

  invariant(
    stream,
    'Expected Parser stream to be available.',
  );

  const line = location.line - 1;
  const start = stream.getStartOfToken();
  const end = stream.getCurrentPosition();