backspace(curString, curStrPos) {
    if (this.pause.status === true) {
      this.setPauseStatus(curString, curStrPos, false);
      return;
    }
    if (this.fadeOut) return this.initFadeOut();

    this.toggleBlinking(false);
    const humanize = this.humanizer(this.backSpeed);

    this.timeout = setTimeout(() => {
      curStrPos = htmlParser.backSpaceHtmlChars(curString, curStrPos, this);
      // replace text with base text + typed characters
      const curStringAtPosition = curString.substring(0, curStrPos);
      this.replaceText(curStringAtPosition);

      // if smartBack is enabled
      if (this.smartBackspace) {
        // the remaining part of the current string is equal of the same part of the new string
        let nextString = this.strings[this.sequence[this.arrayPos + 1]];
        if (
          nextString &&
          curStringAtPosition === nextString.substring(0, curStrPos)
        ) {
          this.stopNum = curStrPos;
        } else {
          this.stopNum = 0;
        }
      }

      // if the number (id of character in current string) is
      // less than the stop number, keep going
      if (curStrPos > this.stopNum) {
        // subtract characters one by one
        curStrPos--;
        // loop the function
        this.backspace(curString, curStrPos);
      } else if (curStrPos <= this.stopNum) {
        // if the stop number has been reached, increase
        // array position to next string
        this.arrayPos++;
        // When looping, begin at the beginning after backspace complete
        if (this.arrayPos === this.strings.length) {
          this.arrayPos = 0;
          this.options.onLastStringBackspaced();
          this.shuffleStringsIfNeeded();
          this.begin();
        } else {
          this.typewrite(this.strings[this.sequence[this.arrayPos]], curStrPos);
        }
      }
      // humanized value for typing
    }, humanize);
  }
Backspaces 1 character at a time
@param {string} curString the current string in the strings array
@param {number} curStrPos the current position in the curString
@private