Update all template_id's which have 'paragraph' for a value

mongo_update.js

/******************************
//collection structure in mongo

{ _id: Object('kjlkjkljlkjlkjlkj'), name: 'val', pages:{'0':{'canvas_objects':{ '0':{ id: '0', template_id: 'paragraph', content: 'something}, ...}}, '1':{...} } },
{ _id: Object('kjlkjkljlkjlkjlkj'), name: 'val', pages:{'0':{'canvas_objects':{ '0':{ id: '0', template_id: 'paragraph', content: 'something}, ...}}, '1':{...} } },
{ _id: Object('kjlkjkljlkjlkjlkj'), name: 'val', pages:{'0':{'canvas_objects':{ '0':{ id: '0', template_id: 'paragraph', content: 'something}, ...}}, '1':{...} } }

*******************************/

var cursor = db.projects.find();
while (cursor.hasNext()) {
    var x = cursor.next();
    for(var i in x.pages){
      for( var j in x.pages[i].canvas_objects){
        canvas_object = x.pages[i].canvas_objects[j];
        if(canvas_object.template_id == 'paragraph'){
          canvas_object.template_id = 'text';
        }
      }
    }
    db.projects.save(x);
}