如何在 javascript 中对 JSON 日期进行排序？

Question

The problem I encounter is that the.sort function doesn't work in my code. So I am wondering why and I also would like to know the solution.

Here is my full code. So I have a set of json data with username, text message, and a date when the user texted. I am able to display the data, but now I want to order them by date.

/**
 * Call to load the test messages.
 */
function loadTestMessages() {
    var request = new XMLHttpRequest();
    request.open('GET', 'data/testmessages.json', true);

    request.onload = function () {
        if (request.status == 200) {
            var messages = JSON.parse(request.response);
            showAllMessages(messages);
        } else {

            console.error("could not load testmessages.json");
        }
    };

    request.onerror = function () {
        console.error("could not load testmessages.json");
    };

    request.send();
}

/**
 * Make a "block" div
 */
function messageDiv(kindClass, html) {
    return '<div class="' + kindClass + '">' + html + '</div>';
}

/**
 * Display all messages 
 * @param {Array} messages
 */
function showAllMessages(messages) {

    for (i = 0; i < messages.length; i++) {
        var name = messages[i].user_id;
        var content = messages[i].content;
        var date = messages[i].created_at;
        var container = document.getElementById('container');
        //   date.sort(function (a, b) { return a - b });
        //   console.info(date);
        container.innerHTML += messageDiv('block', name + ': </br> ' + content + ' </br> ' + date + ' </br> ');
    }

}

loadTestMessages();

Answer 1

I think you want to sort the messages array by the created_at date. If that is correct, you can do it in one line:

messages.sort(function (a, b) { return b.created_at - a.created_at; })

This assumes that created_at holds a Date object. If it is a string instead, then you have to parse it to a Date .

Answer 2

This is a best guess based on your code, but I think you need to sort messages based on the date, then write out the HTML

function showAllMessages(messages) {
    //Sort messages based on the date
    messages.sort(function (m1, m2) { return new Date(m1.created_at) - new Date(m2.created_at) });

    var html = '';
    for (i = 0; i < messages.length; i++) {
        var name = messages[i].user_id;
        var content = messages[i].content;
        var date = messages[i].created_at;
        html += messageDiv('block', name + ': </br> ' + content + ' </br> ' + date + ' </br> ');
    }

    var container = document.getElementById('container');
    container.innerHTML += html;
}

Answer 3

date.sort(function (a, b) { return new Date(b.start).getTime() = new Date(a.start).getTime() });