关于获取jquery对象的长度

/*
17:10 2019/8/6
@author zhangxingshuo
jQuery:"write less, do more"       homepage: https://jquery.com/
jquery-1.12.4.js-|
jquery-2.2.4.js--|- from         jQuery CDN: https://code.jquery.com/
jquery-3.4.1.js--|
┌ ┬ ┐
├ ┼ ┤
└ ┴ ┘

search for "length" and "size()" in three files, the results are as follow:
        1.12.4  2.2.4   3.4.1
length  true    true    true
size()  true    true    false

for more details:
in jquery1.12.4
101-102行:
*/

// The default length of a jQuery object is 0
length: 0,
    /*
    10949-10952行:
    */
// The number of elements contained in the matched element set
    jQuery.fn.size = function() {
        return this.length;
    };
/*
jquery2.2.4
101-102行:
*/

// The default length of a jQuery object is 0
length: 0,
    /*
    9755-9757行:
    */
    size: function() {
    return this.length;
}

/*
jquery3.4.1中
166-167行:
*/
// The default length of a jQuery object is 0
length: 0,