Dynamic CamlJS Expression.js

// code copied from here - http://camljs.codeplex.com/discussions/646023
// CamlJS library hosted here - https://github.com/andrei-markeev/camljs
var dd1_values = ['dd1op1','dd1op2'];
var dd2_values = ['dd2op1'];
var dd3_values = ['dd3op1','dd3op2','dd3op3','dd3op4'];

var dd1_expr_array = [];
for (var i=0;i<dd1_values.length;i++)
{
    dd1_expr_array.push( CamlBuilder.Expression().TextField("Category1").EqualTo(dd1_values[i]) );
}

var all_expr_array = [];
if (dd1_expr_array.length>0)
    all_expr_array.push(CamlBuilder.Expression().Any(dd1_expr_array));
if (dd2_expr_array.length>0)
    all_expr_array.push(CamlBuilder.Expression().Any(dd2_expr_array));
if (dd3_expr_array.length>0)
    all_expr_array.push(CamlBuilder.Expression().Any(dd3_expr_array));

var query = new CamlBuilder().Where().All(all_expr_array).ToString();
console.log(query);

var dd1_expr = CamlBuilder.Expression().TextField("Category1").In(dd1_values[i]);