Javascript : Can't retrieve value from array

Question

I have a code

alert(JSON.stringify((this.shop.get('selectedOrder')).get('orderLines')));

The Result look like this

[{"cart_weight":0,"total_weight":1,"quantity":1,"list_price":1,"discount":0,"ean13":false,"product_image_small":false,"name":"Watermelon1","pos_categ_id":[1,"Others"],"taxes_id":[],"id":2}]

When I run this code

alert((this.shop.get('selectedOrder')).get('orderLines').total_weight);

The result become

undefined

Any export can help ?

I suspect is the double bracket causing the issue [{ }], but I am new to javascript. Not able to solve the issue.

Thank you.

Answer 1

Try alert((this.shop.get('selectedOrder').get('orderLines')[0].total_weight);

As you suspect, your result is not an object (in javascript terminology, any data between {} ) but an array ( [] ) containing one object. So you have to access the first element of your array before accessing the attribute.

Answer 2

Your selected order has multiple lines. You need to choose which line to get the total_weight from. In this case, there is only one line - so you can reference this using [0] . IE:

alert((this.shop.get('selectedOrder')).get('orderLines')[0].total_weight);

If instead, for example, you needed to calculate the weight of the entire order, you could iterate over all the order lines, and calculate the sum.