function hasDistinctElements( arr ) {
	var obj;
	var i;

	obj = {};
	for ( i = 0; i < arr.length; i++ ) {
		if ( hasOwnProp( obj, arr[ i ] ) ) {
			return false;
		}
		obj[ arr[i] ] = true;
	}
	return true;
}
Tests if an array contains distinct elements.

@private
@param {Array} arr - input array
@returns {boolean} boolean indicating if an array contains distinct elements