How to access the property using javascript?

how to access a property for an object within object. I have output like below when i log the value to browser console.

output **** {output: {...}}

when i expand the output i see

output {
    completed: "10",
    total: "20",
}

what i have tried?

i am trying to access the complete property like so

output.completed

but this gives undefined. how should i access completed value?

in this case the expected output is 10.

---

could someone help me with this thanks.