dist/u.packed.js
function(el) {
      if (!el) {
    		return this[0] ? this.first().prevAll().length : -1;
    	}
    	if (''+el === el) {
    		return u.toArray(u(el)).indexOf(this[0]);
    	}
      el = el.ujs ? el[0] : el;
    	return u.toArray(this).indexOf(el);
    }
function(el) {
      if (!el) {
    		return this[0] ? this.first().prevAll().length : -1;
    	}
    	if (''+el === el) {
    		return u.toArray(u(el)).indexOf(this[0]);
    	}
      el = el.ujs ? el[0] : el;
    	return u.toArray(this).indexOf(el);
    }
function ( el ) { if ( ! el ) { return this [ 0 ] ? this . first ( ) . prevAll ( ) . length : - 1 ; } if ( '' + el === el ) { return u . toArray ( u ( el ) ) . indexOf ( this [ 0 ] ) ; } el = el . ujs ? el [ 0 ] : el ; return u . toArray ( this ) . indexOf ( el ) ; }
index method
get the index of an element
@param  {object|string} [el] - elements or css selector
@return {number}               index
index method get the index of an element