Sorting of array containing objects

jsbin.gisiwu.js

(function(scope) {
  function cmp(a, b, mul) {
    return (a == b ? 0 : (a < b ? -1 : 1)) * mul;
  }
  
  function ocmp() {
    var _sorting = [].slice.call(arguments).filter(function(v) {
      return v != null;
    }).map(function(v) {
      if (typeof v == 'string') {
        return {key: v, mul: 1};
      } else {
        return {key: v[0], mul: v[1]};
      }
    });
    return function(a, b) {
      return _sorting.reduce(function(mem, sort) {
        return mem - cmp(a[sort.key], b[sort.key], sort.mul);
      }, 0);
    };
  }
  
  scope.ocmp = ocmp;
}(window));

var a = [
  {name: 'aaa', age: 11, uid: 44, desc: 'obj-1'},
  {name: 'aaa', age: 10, uid: 55, desc: 'obj-2'},
  {name: 'bbb', age: 20, uid: 22, desc: 'obj-3'},
  {name: 'bbb', age: 19, uid: 66, desc: 'obj-4'},
];

console.log(a.sort(ocmp('uid', 'age')));