Question

I have an object that looks like:

var object = [
    {"begin":0,  "end":20}, 
    {"begin":30, "end":300},
    {"begin":40, "end":60}, 
    {"begin":40, "end":50},
    {"begin":80, "end":100},
    {"begin":80, "end":100},
    {"begin":350,"end":370}
]

I would like to iterate over this object and sort it in the following form:

0   to 20   -> start here
30  to 300  -> next smallest number from 20 is 30
350 to 370  -> start from previous `end`, next number after 300 is 350.

// now, since there is no larger number than 370, start loop again.
40  to 60   -> start from 40 since this is the smallest unused number
80  to 100  -> next unused smallest number from 60 is 80

// now, since there is no larger unused number than 100, start loop again.
40  to 50
80  to 100

Either returning the same array or a new array would be fine.

Any help is always appreciated.

Answer 1

See a working example here: http://jsfiddle.net/bXNLT/2/

function sortItems(items) {
    items = items.slice() // make a copy
        // sort by "begin", in case the 
        // data isn't pre-sorted
        .sort(function(a,b) {
            return a.begin - b.begin;
        });
    var sorted = [], 
        idx = 0, 
        item;
    while (items.length) {
        // move the current item into the sorted array
        item = items.splice(idx, 1)[0];
        sorted.push(item);
        // find next index
        for (; idx<items.length; idx++) {
            if (items[idx] && items[idx].begin > item.end) {
                break;   
            }
        }
        // reset to 0 if we went too far
        idx = idx < items.length ? idx : 0;
    }
    return sorted;
}

Usage:

var arr = [
    {"begin":0,  "end":20}, 
    {"begin":30, "end":300},
    {"begin":40, "end":60}, 
    {"begin":40, "end":50},
    {"begin":80, "end":100},
    {"begin":80, "end":100},
    {"begin":350,"end":370}
];
sortItems(arr); // sorted as you specify