dist/u.packed.js
function(attr, index, attrCamel) {
      return this.each(function(i, el) {
        if (attr !== undefined) {
          attrCamel = u.toCamel(u.toDash(attr));
          if ((index = el[u._id]) !== undefined) {
            el.dataset ? delete el.dataset[attrCamel] : el.removeAttribute('data-' + attr);
            delete u._data[index][attrCamel];
          }
        }
      });
    }
function(attr, index, attrCamel) {
      return this.each(function(i, el) {
        if (attr !== undefined) {
          attrCamel = u.toCamel(u.toDash(attr));
          if ((index = el[u._id]) !== undefined) {
            el.dataset ? delete el.dataset[attrCamel] : el.removeAttribute('data-' + attr);
            delete u._data[index][attrCamel];
          }
        }
      });
    }
function ( attr , index , attrCamel ) { return this . each ( function ( i , el ) { if ( attr !== undefined ) { attrCamel = u . toCamel ( u . toDash ( attr ) ) ; if ( ( index = el [ u . _id ] ) !== undefined ) { el . dataset ? delete el . dataset [ attrCamel ] : el . removeAttribute ( 'data-' + attr ) ; delete u . _data [ index ] [ attrCamel ] ; } } } ) ; }
removeData method
remove data attribute
@param  {string}    attr        - attribute name
@param  {undefined} [index]     - index placeholder
@param  {undefined} [attrCamel] - placeholder for attribute name in camelCase
@return {object}                  this
removeData method remove data attribute