Use Array.prototype.sort() with a custom compare function to do the descending sort first:
champions.sort(function(a, b) { return b.level - a.level }).slice(...
Even nicer with ES6:
champions.sort((a, b) => b.level - a.level).slice(...
Use Array.prototype.sort() with a custom compare function to do the descending sort first:
champions.sort(function(a, b) { return b.level - a.level }).slice(...
Even nicer with ES6:
champions.sort((a, b) => b.level - a.level).slice(...