什么是x>>> 0呢？

可能重复：

零填充位移0有什么用呢？ （a>>> 0）

我一直在尝试我的一个项目中的一些函数式编程概念，我正在阅读 Array.prototype.map ，这是ES5中的新功能，如下所示：

I've been trying out some functional programming concepts in a project of mine and I was reading about Array.prototype.map, which is new in ES5 and looks like this:

Array.prototype.map = function(fun) {
    "use strict";
    if (this === void 0 || this === null) {
        throw new TypeError();
    }
    var t = Object(this);
    var len = t.length >>> 0;
    if (typeof fun !== "function") {
        throw new TypeError();
    }
    var res = new Array(len);
    var thisp = arguments[1];
    for (var i = 0; i < len; i++) {
        if (i in t) {
            res[i] = fun.call(thisp, t[i], i, t);
        }
    }
    return res;
};

我想知道为什么它正在做 t.length>&gt ;> 0 。因为它似乎没有做任何事情。 x>>> 0 // - > X ！ （只要x是一个数字，显然）

What I'm wondering is why it's doing t.length >>> 0. Because it doesn't seem to do anything. x >>> 0 //-> x! (as long as x is a number, obviously)

另外，请注意我不知道按位运算符是如何工作的。

Also, note that I don't know how bitwise operators work.