jquery 源码学习

jquery：grep 函数

grep: function( elems, callback, inv ) {

var ret = [], retVal;

inv = !!inv; //变成boolen, 默认是false

 

// Go through the array, only saving the items

// that pass the validator function

for ( var i = 0, length = elems.length; i < length; i++ ) {

retVal = !!callback( elems[ i ], i );  // 将满足callback函数中的条件的值返回

if ( inv !== retVal ) {

ret.push( elems[ i ] );

}

}

 

return ret;

},

 

例子 :

$.grep([0,1,2],function(n,i){
   return n >0;
 });

Result:

[1, 2]