code: function addDeprecatedGetters(obj, props) {
    var proto = obj.prototype;
    var i, l, prop, getter;
    for (i = 0, l = props.length; i < l; i++) {
      prop = props[i];
      getter = 'get' + capitalize(prop);
      proto[getter] = util.deprecate(
        createGetter(prop),
        'use `.' + prop + '` instead of `.' + getter + '()`'
      );
    }
  
    function createGetter(prop) {
      return function () {
        var delegate = this[prop];
        return typeof delegate == 'function' ?
          delegate.apply(this, arguments) :
          delegate;
      };
    }
  }
docs: Batch-deprecate "getters" from an object's prototype.