mergeMeetingSolution.js

function mergeRanges(meetings) {

    // sort by start times, slice will return a shallow copy of the array, not affecting original array
    var sortedMeetings = meetings.slice().sort(function(a, b) {
        return a.startTime > b.startTime ? 1 : -1;
    });

    // initialize mergedMeetings with the earliest meeting
    var mergedMeetings = [sortedMeetings[0]];

    for (var i = 1; i < sortedMeetings.length; i++) {

        var currentMeeting    = sortedMeetings[i];
        var lastMergedMeeting = mergedMeetings[mergedMeetings.length - 1];

        // if the current and last meetings overlap, use the latest end time
        // objects, and arrays (which are objects) all are passed by reference. thus change will be recorded.
        if (currentMeeting.startTime <= lastMergedMeeting.endTime) {
            lastMergedMeeting.endTime = Math.max(lastMergedMeeting.endTime, currentMeeting.endTime);

        // add the current meeting since it doesn't overlap
        } else {
            mergedMeetings.push(currentMeeting);
        }
    }

    return mergedMeetings;
}


meetings =   [
    {startTime: 0,  endTime: 1},
    {startTime: 3,  endTime: 5},
    {startTime: 4,  endTime: 8},
    {startTime: 10, endTime: 12},
    {startTime: 9,  endTime: 10},
];

//var res = meetings.slice();
var res = mergeRanges(meetings);
console.log(meetings);
console.log("break");
console.log(res);