Conditionally add properties to elements of array with yq (version 4) - arrays

Question

I have a YAML document that contains an array. I would like to conditionally add properties to the elements of that array using yq version 4 from mikefarah.
Here is a sample YAML document.
name: "My Pets"
pets:
- name: "cat"
age: 8
- name: "dog"
age: 3
- name: "mouse"
age: 1
I would like to transform this into,
name: "My Pets"
pets:
- name: "cat"
age: 8
shots: cat.upToDate
- name: "dog"
age: 3
shots: dog.upToDate
- name: "mouse"
age: 1
shots: mouse.upToDate
where we add a shots property to each element of pets. The value of shots should be whatever the name value is, dot, upToDate.
I'm trying something like this,
yq eval '.pets[] | select(.name == "cat").shots = "cat.upToDate"' test.yaml
but that produces,
name: "cat"
age: 8
shots: cat.upToDate
name: "dog"
age: 3
name: "mouse"
age: 1
I need to preserve the entire original YAML document and just insert the shots property.
This is close but missing all of the other pets.
yq eval '.pets = (.pets[] | select(.name == "cat").shots = "cats.upToDate")' test.yaml
It produces,
name: "My Pets"
pets:
name: "cat"
age: 8
shots: cats.upToDate
I'm thinking maybe we could store the name of the pet in a variable and reference that later, but v4 is brand new to me today.
I would prefer to have a one-liner so that I don't have to filter on .name. This array has less than 10 elements so I could easily hard-code the name and call yq 10 times.
Any thoughts or suggestions? Many thanks, Weldon

Answer 1

Use |=, e.g. like so:
yq eval '.pets[] |= (.shots = (.name + ".upToDate"))' pets.yaml