player/js/utils/expressions/TextInterface.js

var TextExpressionInterface = (function () {
  return function (elem) {
    var _prevValue, _sourceText;
    function _thisLayerFunction(name) {
      switch(name) {
        case 'ADBE Text Document':
          return _thisLayerFunction.sourceText;
      }
    }
    Object.defineProperty(_thisLayerFunction, 'sourceText', {
      get: function () {
        elem.textProperty.getValue()
        var stringValue = elem.textProperty.currentData.t;
        if(stringValue !== _prevValue) {
          elem.textProperty.currentData.t = _prevValue;
          _sourceText = new String(stringValue);
          // If stringValue is an empty string, eval returns undefined, so it has to be returned as a String primitive
          _sourceText.value = stringValue ? stringValue : new String(stringValue);
        }
        return _sourceText;
      }
    });
    return _thisLayerFunction;
  };
}());