javascript function overloading...

func-overload.js

var get = (function() {
  var overrides = {
      getAll: function() {
        console.log('return all...');
        return this;
      },
      getById: function(args) {
        console.log('return by id:' + args);
        return this;
      },    
      getByExpr: function(args) {
        console.log('return by expression: ' + args);
        return this;
      }
    }

    return function () {
      var args = [].slice.call(arguments, 0);
      if (args.length === 0) {
        return overrides['getAll'].apply(this, args);
      }
      if (args.length === 1) {
        if (typeof args[0] === 'string') {
          return overrides['getByExpr'].apply(this, args);
        }
        if (typeof args[0] === 'number') {
          return overrides['getById'].apply(this, args);
        }
        throw "invalid argument";
      }
    };
}());

get();
get(5);
get('id > 5');