query custom objects using several tags

My database contains custom objects that have several tags each. I"m trying to retrieve objects that have 2 tags using tags_array, but it seems that I can't get the correct syntax. my query:

Cloud.Objects.query({

    classname: 'plant',
    page: 1,
    per_page: 10,

    where: "{tags_array:{1,2},another_field:3}"
    });

this option throw the following error: 400: Error: Unexpected token }

any help would be much appreciated!