Q: Checking the Specific Minutes and Seconds in Moment.js When a user selects an end day on my calendar component, I have the following:
moment(currentTime.end).endOf('day').format('YYYY-MM-DD');

Usually the date range is preset but users can also adjust the time range within the date range. 
If a user sets the end time to 23:59:59, I want to add an additional second and give them 24 hours. Is there a way in moment.js to recognize when a certain date set to the endOfDay, and is there a way to add a second? 

A: 
use .add(1, 'second') to add a second
use .format('HH:mm:ss') === '23:59:59 to check is time end of day

e.g.:
var currentTime = {start: xxx, end: xxx};

// get the endTime by HH:mm:ss
var endTime = moment(currentTime.end).format('HH:mm:ss');
if (endTime === '23:59:59') {

    // If true add one second and return the format you need
    endTime = moment(currentTime.end).add(1, 'second').formet('YYYY-MM-DD');

} else {

    // If false just return the format you need
    endTime = moment(currentTime.end).formet('YYYY-MM-DD');

}

