jQuery source code parsing (vi) the difference between the $ .each and $ .map

$ .Each mainly used to iterate or objects, for example:

var arr = [11,12,13,14 ]; 
$ .each (arr, function (element, index) {     // iterate array arr 
    the console.log (element, index)             // print element and index 
})

Output is as follows:

Although the $ .map also iterate, but it can generate an array, you can simply return a value in the function, as follows:

var arr = [11,12,13,14 ]; 
 var B = $ .map (arr, function (Element, index) {     // iterate array arr 
    IF (Element% 2 == 0) return Element                     // return only can figure 2 is divisible

writer by: Desert QQ: 22969969

})
console.log(b)

writer by: Desert QQ: 22969969

Output:

Summary: . $ .Each is used to iterate, $ map in addition to iterate, filtered, and can also generate a new array, of course, not necessarily the filter, any logic can be done in the function in the map, as long as the return value can meet the requirements of