为什么在JS数组上调用.toString时会出现“ object Object”？

Question

I'm trying to look at all the cookies in a given document with this:

function get_cookies_array() {
    var cookies = {};

    if (document.cookie && document.cookie != '') {
        var split = document.cookie.split(';');

        for (var i = 0; i < split.length; i++) {
            var name_value = split[i].split("=");
            name_value[0] = name_value[0].replace(/^ /, '');
            cookies[decodeURIComponent(name_value[0])] = decodeURIComponent(name_value[1]);
        }
    }

    return cookies;
}

var cookies = get_cookies_array();

alert(cookies.toString());

However, what i'm seeing in the alert box is

[object Object]

I was expecting a comma separated list of values. What am I doing wrong?

Answer 1

The value being returned is not an array. It's a plain object. Presumably you do want to use an object here, so that you can use string-valued keys. You can print out its contents like so:

var cookies = get_cookies_array();

console.log(JSON.stringify(cookies));

Or line by line:

Object.keys(cookies).forEach(function (key) {
    console.log(key, ' - ', cookies[key]);
});

Answer 2

Replace var cookies = {}; with var cookies = []; so that you are dealing with an Array instead of an Object.

Then, because you are using an associative array, also change your writing into array like this:

cookies.push([decodeURIComponent(name_value[0]), decodeURIComponent(name_value[1])]);