Question

I have this code to iterate through an array of objects:

for (vehicleIndex in scenes[sceneID].vehicles) {
  vehicleID = scenes[sceneID].vehicles[vehicleIndex];
  ...
}

but I need to know how to determine the number of items being iterated through so that on the final item, I can execute a particular function. How do I do this?

Answer 1

Example in ES5:

Object.keys( scenes[sceneID].vehicles ).forEach(function( vehicle, index, arr ) {
    if( index === arr.length - 1 ) {
        // do something on last entry
    }
});

Even tho, “last” just means the last element which was looped over. Since there is specific order within a Javascript object (they are infact unordered). However, we could sort the object key names manually by just chaining a .sort() before the .forEach()