Question

I have following array:

var events = [
 {id : 1, start : 100, end : 120},
 {id : 2, start : 60, end : 240},
 {id : 3, start : 700, end : 720}
];

How do I sort based on start index while preserving the id something like:

var events = [
 {id : 2, start : 60, end : 240},
 {id : 1, start : 100, end : 120},
 {id : 3, start : 700, end : 720}
];

I tried:

events.sort()
events.sort(function(a,b){return a-b});

But neither worked 🙁

Answer 1

The array.sort(..) function passes two elements of the array (which are being compared) to the comparator function you specify. Since, in that case, a and b are objects like {id : 3, start : 700, end : 720}, they can not be really compared like a-b.

Use this instead:

events.sort(function(a,b){return a.start - b.start;});