使用Moment.js以分钟格式比较时间，该格式不会在小时上重置

Question

I am trying to create a count up timer based on an object's modified time (formatted like: 2014-02-19T18:49:15) and comparing it to the current time using Moment.js. But when it reaches 60 minutes, it restarts back to 0. I think this is because I am comparing just the minutes here or at least using math to change the milliseconds to a whole number format? I am not quite sure, I got excited when I got the minutes to format correctly. The difference in minutes is all I want to return. So for example after an hour and a half I want a returned value of '90'.

function() {
    return function(entry) {
        var elpTime = Math.floor(((Date.parse(moment()) - Date.parse(entry.arrival_time)) / (1000*60)) % 60);

        return elpTime;
    }
};

Here is an example of the object.

{
patient_id: 198,
arrival_time: "2014-02-19T18:49:15",
last_modified: "2014-02-19T18:49:15"
}

I know I am missing something probably obvious. But any help is appreciated. Thanks!

(Should be noted that I am using this as apart of a filter function in Angular.js. But I stripped it out since I didn't think it was nessacary)

Answer 1

Since you are using Moment.js you can use the built in diff function to return the time period between two moments.

function() {
    return function(entry) {
        var elpTime = moment(entry.arrival_time).diff(moment(),'minutes');

        return elpTime;
    }
};

From the documentation:

The supported measurements are years, months, weeks, days, hours, minutes, and seconds.

By default, moment#diff will return number rounded down. If you want the floating point number, pass true as the third argument. Before 2.0.0, moment#diff returned rounded number, not a rounded down number.

Example from documentation:

var a = moment([2008, 6]);
var b = moment([2007, 0]);
a.diff(b, 'years');       // 1
a.diff(b, 'years', true); // 1.5