https://www.v2ex.com/t/364775#reply0

test.js

var idLevel = 9999;
var config = null;

function getIdLevel(id) {
  if (id == 1 || id == 3) return 0;
  if (id == 2 || id == 4) return 1;
  return 2;
}

for (var i : items) {
  var item = items[i];
  if (item['config'] && getIdLevel(item['id']) <= idLevel) {
    config = item['config'];
    idLevel = getIdLevel(item['id']);
  }
}