Jquery 1.9.1源码分析系列（十二）之筛选操作

jQuery.fn.find( selector )

if ( typeof selector !== "string" ) { self = this; return this.pushStack( jQuery( selector ).filter(function() {  for ( i = 0; i < len; i++ ) {   if ( jQuery.contains( self[ i ], this ) ) {    return true;   }  } }) );}

ret = [];for ( i = 0; i < len; i++ ) { //第二个参数是表示context jQuery.find( selector, this[ i ], ret );}//$( selector, context )变成$( context ).find( selector )，需要去重和pushStackret = this.pushStack( len > 1 ? jQuery.unique( ret ) : ret );ret.selector = ( this.selector ? this.selector + " " : "" ) + selector;return ret;

jQuery.fn.closest( selectors, context )

pos = rneedsContext.test( selectors ) || typeof selectors !== "string" ?jQuery( selectors, context || this.context ) :0;

for ( ; i < l; i++ ) { cur = this[i]; while ( cur && cur.ownerDocument && cur !== context && cur.nodeType !== 11 ) {  if ( pos ? pos.index(cur) > -1 : jQuery.find.matchesSelector(cur, selectors) ) {   ret.push( cur );   break;  }  cur = cur.parentNode; }}return this.pushStack( ret.length > 1 ? jQuery.unique( ret ) : ret );

jQuery.each({  parent: function( elem ) {…},  parents: function( elem ) {…},  parentsUntil: function( elem, i, until ) {…},  next: function( elem ) {…},  prev: function( elem ) {…},  nextAll: function( elem ) {…},  prevAll: function( elem ) {…},  nextUntil: function( elem, i, until ) {…},  prevUntil: function( elem, i, until ) {…},  siblings: function( elem ) {…},  children: function( elem ) {…},  contents: function( elem ) {…} }, function( name, fn ) {  jQuery.fn[ name ] = function( until, selector ) {   var ret = jQuery.map( this, fn, until );   //过滤   ...   return this.pushStack( ret );  }; });

if ( !runtil.test( name ) ) { selector = until;}

if ( selector && typeof selector === "string" ) { ret = jQuery.filter( selector, ret );}

ret = this.length > 1 && !guaranteedUnique[ name ] ? jQuery.unique( ret ) : ret;

if ( this.length > 1 && rparentsprev.test( name ) ) { ret = ret.reverse();}

return this.pushStack( ret );　

dir: function( elem, dir, until ) { var matched = [], cur = elem[ dir ]; while ( cur && cur.nodeType !== 9 && (until === undefined || cur.nodeType !== 1 || !jQuery( cur ).is( until )) ) {  if ( cur.nodeType === 1 ) {   matched.push( cur );  }  cur = cur[dir]; } return matched;},//获取节点n及其兄弟节点中非elem的节点集合rsibling: function( n, elem ) { var r = []; for ( ; n; n = n.nextSibling ) {  if ( n.nodeType === 1 && n !== elem ) {   r.push( n );  } } return r;}//找到当前元素cur的下一个dir为止function sibling( cur, dir ) {  do {   cur = cur[ dir ];  } while ( cur && cur.nodeType !== 1 );  return cur; }　

jQuery.fn.add( selector, context )和jQuery.fn. addBack( selector )

add: function( selector, context ) { var set = typeof selector === "string" ?   jQuery( selector, context ) :   jQuery.makeArray( selector && selector.nodeType ? [ selector ] : selector ),  //把selector表达式获取的结果集拼接到当前对象上  all = jQuery.merge( this.get(), set ); //返回新的拼接结果 return this.pushStack( jQuery.unique(all) );}　　jQuery.fn.add和jQuery.fn.not相对应。jQuery.fn.not后面再说。　　jQuery.fn.addBack将之前匹配的元素加入到当前匹配的元素中，并以新的jQuery对象的形式返回。addBack: function( selector ) { return this.add( selector == null ?  this.prevObject : this.prevObject.filter(selector)  );}jQuery.fn.andSelf = jQuery.fn.addBack;　　jQuery.fn.not( selector )和jQuery.fn.filter( selector )not: function( selector ) { return this.pushStack( winnow(this, selector, false) );}filter: function( selector ) { return this.pushStack( winnow(this, selector, true) );},

//执行相同的过滤或者不过滤的功能function winnow( elements, qualifier, keep ) { // Can't pass null or undefined to indexOf in Firefox 4 // Set to 0 to skip string check qualifier = qualifier || 0; //如果过滤条件是函数，则通过过滤函数过滤 if ( jQuery.isFunction( qualifier ) ) {  return jQuery.grep(elements, function( elem, i ) {   var retVal = !!qualifier.call( elem, i, elem );   return retVal === keep;  }); //如果过滤条件是DOM相关类型，通过比较节点是否相同来过滤 } else if ( qualifier.nodeType ) {  return jQuery.grep(elements, function( elem ) {   return ( elem === qualifier ) === keep;  }); //如果过滤条件是字符串 } else if ( typeof qualifier === "string" ) {  //过滤出elements中的节点元素  var filtered = jQuery.grep(elements, function( elem ) {   return elem.nodeType === 1;  });  // 其中isSimple = /^.[^:#/[/.,]*$/  if ( isSimple.test( qualifier ) ) {   return jQuery.filter(qualifier, filtered, !keep);  } else {   //查找filtered中满足筛选条件qualifier的节点   qualifier = jQuery.filter( qualifier, filtered );  } } //过滤出elements中满足过滤条件的元素 return jQuery.grep(elements, function( elem ) {  return ( jQuery.inArray( elem, qualifier ) >= 0 ) === keep; });}

jQuery.filter: function( expr, elems, not ) { if ( not ) {  expr = ":not(" + expr + ")"; } //其中matchesSelector和matches是Sizzle中的函数。matchesSelector是判断单个元素elem是否满足表达式expr，matches是查找元素集合elems中满足表达式expr的项 return elems.length === 1 ?  jQuery.find.matchesSelector(elems[0], expr) ? [ elems[0] ] : [] :  jQuery.find.matches(expr, elems);},jQuery.fn.index( elem )

if ( !elem ) { return ( this[0] && this[0].parentNode ) ? this.first().prevAll().length : -1;}

if ( typeof elem === "string" ) { //在数组jQuery( elem )中搜索指定的值，并返回其索引值 return jQuery.inArray( this[0], jQuery( elem ) );}

return jQuery.inArray(elem.jquery ? elem[0] : elem, this );