jquery1.0源码解读
filter函数
1.0源码:1
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162expr: {
"": "m[2]== '*'||a.nodeName.toUpperCase()==m[2].toUpperCase()",
"#": "a.getAttribute('id')&&a.getAttribute('id')==m[2]",
":": {
// Position Checks
lt: "i<m[3]-0",
gt: "i>m[3]-0",
nth: "m[3]-0==i",
eq: "m[3]-0==i",
first: "i==0",
last: "i==r.length-1",
even: "i%2==0",
odd: "i%2",
// Child Checks
"first-child": "jQuery.sibling(a,0).cur",
"last-child": "jQuery.sibling(a,0).last",
"only-child": "jQuery.sibling(a).length==1",
// Parent Checks
parent: "a.childNodes.length",
empty: "!a.childNodes.length",
// Text Check
contains: "(a.innerText||a.innerHTML).indexOf(m[3])>=0",
// Visibility
visible: "a.type!='hidden'&&jQuery.css(a,'display')!='none'&&jQuery.css(a,'visibility')!='hidden'",
hidden: "a.type=='hidden'||jQuery.css(a,'display')=='none'||jQuery.css(a,'visibility')=='hidden'",
// Form elements
enabled: "!a.disabled",
disabled: "a.disabled",
checked: "a.checked",
selected: "a.selected"
},
".": "jQuery.className.has(a,m[2])",
"@": {
"=": "z==m[4]",
"!=": "z!=m[4]",
"^=": "!z.indexOf(m[4])",
"$=": "z.substr(z.length - m[4].length,m[4].length)==m[4]",
"*=": "z.indexOf(m[4])>=0",
"": "z"
},
"[": "jQuery.find(m[2],a).length"
},
// The regular expressions that power the parsing engine
//正则提供解析能力
parse: [
// Match: [@value='test'], [@foo]
[ "\\[ *(@)S *([!*$^=]*) *Q\\]", 1 ],
// Match: [div], [div p]
[ "(\\[)Q\\]", 0 ],
// Match: :contains('foo') * 匹配前面的子表达式任意次。例如，zo*能匹配“z”，也能匹配“zo”以及“zoo”。
[ "(:)S\\(Q\\)", 0 ],//(:)([a-z*_-][a-z0-9_-]*)\\(*'?\"?([^'\"]*?)'?\"? *\\)
// Match: :even, :last-chlid
[ "([:.#]*)S", 0 ]
],
//t 一般为字符串
//r为 元素集合
filter: function(t,r,not) {
// Figure out if we're doing regular, or inverse, filtering
//not 为undefined的时候 not!==false返回true
//所以g = jQuery.grep
//grep静态函数第三个参数为true的话就返回不满足条件的新的元素
//t为:not(.example)的时候就会递归调用
//最终调用的是grep函数
var g = not !== false ? jQuery.grep :
function(a,f) {return jQuery.grep(a,f,true);};
//not(.example) 符合正则
while ( t && /^[a-z[({<*:.#]/i.test(t) ) {
var p = jQuery.parse;//parse数组
for ( var i = 0; i < p.length; i++ ) {
var re = new RegExp( "^" + p[i][0]
// Look for a string-like sequence
.replace( 'S', "([a-z*_-][a-z0-9_-]*)" )
// Look for something (optionally) enclosed with quotes
.replace( 'Q', " *'?\"?([^'\"]*?)'?\"? *" ), "i" );
var m = re.exec( t );
//:not(.example)递归调用到这
//满足.example的就是[ "([:.#]*)S", 0 ]
if ( m ) {
// Re-organize the match
if ( p[i][1] )//Match: [@value='test'], [@foo] p[i][1] 为1
m = ["", m[1], m[3], m[2], m[4]];
// Remove what we just matched
t = t.replace( re, "" );//一般t就为空了,所以最后就跳出while循环
//.example的话 t就为空了
break;//这里就退出循环了
}
}
// :not() is a special case that can be optomized by
// keeping it out of the expression list
//:not(.example)
//m[0] = :not(.example)
//m[1] = :
//m[2] = not
//m[3] = .example
if ( m[1] == ":" && m[2] == "not" )
r = jQuery.filter(m[3],r,false).r;//递归下 到里面grep就是为包装grep的函数了
// Otherwise, find the expression to execute
//m[0] = .example
//m[1] = .
//m[2] = example
else {
//m[1]为.那么 在expr数组中就返回jQuery.className.has(a,m[2])
var f = jQuery.expr[m[1]];
if ( f.constructor != String )
f = jQuery.expr[m[1]][m[2]];
// Build a custom macro to enclose it
eval("f = function(a,i){" +
( m[1] == "@" ? "z=jQuery.attr(a,m[3]);" : "" ) +
"return " + f + "}");
// Execute it against the current filter
//f 为 function(a,i){
// return jQuery.className.has(a,m[2]) //m[2] 此时为'example'
//}
//再结合 g = function(a,f) {return jQuery.grep(a,f,true);};
//相当于jQuery.grep(r,f,true)
r = g( r, f );
}
}
// Return an array of filtered elements (r)
// and the modified expression string (t)
return { r: r, t: t };
},
className: {
add: function(o,c){
if (jQuery.className.has(o,c)) return;
o.className += ( o.className ? " " : "" ) + c;
},
remove: function(o,c){
o.className = !c ? "" :
o.className.replace(
new RegExp("(^|\\s*\\b[^-])"+c+"($|\\b(?=[^-]))", "g"), "");
},
has: function(e,a) {
if ( e.className != undefined )
e = e.className;//直接把e.className给e
//以a开头和结束
//或者a前面和后面是空格
return new RegExp("(^|\\s)" + a + "(\\s|$)").test(e);
}
},
