Is it possible to group Tumblr posts by day?

Question

Is it possible to hack the date tag on a Tumblr page to display posts like this:

Today

• Post 1
• Post 2
• Post 3

Yesterday

• Post 4
• Post 5
• Post 6

Monday

• Post 7
• Post 8
• Post 9

'Today' and 'Yesterday' can be replaced by 'Wednesday' and 'Tuesday' if need be.

Answer 1

Tumblr's templating does not contemplate grouping. The only way to do it is to manually (i.e. via javascript) group the posts and create headlines between each group.

Assuming jQuery for brevity:

var days = {};

//group posts by day
$('.post').each(function (i, el) {
    //get timestamp from post
    var timestamp = new Date($(el).data('timestamp')*1000);

    //set to midnight of day
    timestamp.setHours(0,0,0,0);

    //create array for each day if it doesn't already exist
    days[timestamp] = days[timestamp] || [];

    days[timestamp].push(el);
});

//now "days" will be an array of days each containing an array of posts
//print the day of the week above the first post of each day
var dayNames = ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'];
$.each(days, function (dayTimestamp, dayPosts) {
    //create headline with day of the week in it
    var $h = $('<h1>').text(dayNames[dayTimestamp.getDay()]);

    //add it before the first post of the day
    $h.insertBefore(dayPosts[0]);
});

And in your template, make sure you have this for each post:

<div class="post" data-timestamp="{Timestamp}">...content...</div>

Untested code but it should get you started