This specific regular expression pattern checks that the received parameter value:

* `^`: starts with the following characters, doesn't have characters before.
* `fixedquery`: has the exact value `fixedquery`.
* `$`: ends there, doesn't have any more characters after `fixedquery`.

object.\n * @method\n * @memberof Popper.Utils\n * @param {dataObject} data\n * @param {Array} modifiers\n * @param {String} ends - Optional modifier name used as stopper\n * @returns {dataObject}\n */\nexport default function runModifiers(modifiers, data, ends) {\n  const modifiersToRun = ends === undefined\n    ? modifiers\n    : modifiers.slice(0, findIndex(modifiers, 'name', ends));\n\n  modifiersToRun.forEach(modifier => {\n    if (modifier['function']) { // eslint-disable-line dot-notation\n    ...

    final char[] array;
    final int start;
    final int end;

    CharArrayAsList(char[] array) {
      this(array, 0, array.length);
    }

    CharArrayAsList(char[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override

    final short[] array;
    final int start;
    final int end;

    ShortArrayAsList(short[] array) {
      this(array, 0, array.length);
    }

    ShortArrayAsList(short[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override

    final short[] array;
    final int start;
    final int end;

    ShortArrayAsList(short[] array) {
      this(array, 0, array.length);
    }

    ShortArrayAsList(short[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override

    testRotate(new char[] {'1'}, 1, 0, 1, new char[] {'1'});
    testRotate(new char[] {'1'}, 1, 1, 1, new char[] {'1'});

    // Rotate the central 5 elements, leaving the ends as-is
    testRotate(
        new char[] {'0', '1', '2', '3', '4', '5', '6'},
        -6,
        1,
        6,
        new char[] {'0', '2', '3', '4', '5', '1', '6'});
    testRotate(

    }

    @Override
    public Optional<Long> lengthIfKnown() {
      return Optional.of((long) seq.length());
    }

    /**
     * Returns an iterator over the lines in the string. If the string ends in a newline, a final
     * empty string is not included, to match the behavior of BufferedReader/LineReader.readLine().
     */
    private Iterator<String> linesIterator() {
      return new AbstractIterator<String>() {

    }

    @Override
    public Optional<Long> lengthIfKnown() {
      return Optional.of((long) seq.length());
    }

    /**
     * Returns an iterator over the lines in the string. If the string ends in a newline, a final
     * empty string is not included, to match the behavior of BufferedReader/LineReader.readLine().
     */
    private Iterator<String> linesIterator() {
      return new AbstractIterator<String>() {

    final char[] array;
    final int start;
    final int end;

    CharArrayAsList(char[] array) {
      this(array, 0, array.length);
    }

    CharArrayAsList(char[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override

    final float[] array;
    final int start;
    final int end;

    FloatArrayAsList(float[] array) {
      this(array, 0, array.length);
    }

    FloatArrayAsList(float[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override