  peekMultichar: function() {
    var ch = this.text.charAt(this.index);
    var peek = this.peek();
    if (!peek) {
      return ch;
    }
    var cp1 = ch.charCodeAt(0);
    var cp2 = peek.charCodeAt(0);
    if (cp1 >= 0xD800 && cp1 <= 0xDBFF && cp2 >= 0xDC00 && cp2 <= 0xDFFF) {
      return ch + peek;
    }
    return ch;
  },
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.