text(tweenProp) {
    if (!KEC[tweenProp] && this.valuesEnd[tweenProp]) {
      const chars = this._textChars;
      let charsets = charSet[defaultOptions$1.textChars];

      if (chars in charSet) {
        charsets = charSet[chars];
      } else if (chars && chars.length) {
        charsets = chars;
      }

      KEC[tweenProp] = (elem, a, b, v) => {
        let initialText = '';
        let endText = '';
        const finalText = b === '' ? ' ' : b;
        const firstLetterA = a.substring(0);
        const firstLetterB = b.substring(0);
        /* eslint-disable */
        const pointer = charsets[(Math.random() * charsets.length) >> 0];

        if (a === ' ') {
          endText = firstLetterB
            .substring(Math.min(v * firstLetterB.length, firstLetterB.length) >> 0, 0);
          elem.innerHTML = v < 1 ? ((endText + pointer)) : finalText;
        } else if (b === ' ') {
          initialText = firstLetterA
            .substring(0, Math.min((1 - v) * firstLetterA.length, firstLetterA.length) >> 0);
          elem.innerHTML = v < 1 ? ((initialText + pointer)) : finalText;
        } else {
          initialText = firstLetterA
            .substring(firstLetterA.length,
              Math.min(v * firstLetterA.length, firstLetterA.length) >> 0);
          endText = firstLetterB
            .substring(0, Math.min(v * firstLetterB.length, firstLetterB.length) >> 0);
          elem.innerHTML = v < 1 ? ((endText + pointer + initialText)) : finalText;
        }
        /* eslint-enable */
      };
    }
  }
onStartWrite.text

Sets the property update function.
@param {string} tweenProp the property name