Earlier quoted context omitted.
How would you define the `printMessage` function? The `pet` object doesn't have context about `staff`, and the `filter` function is filtering staff, not pets. It could return staff that have both cats and dogs, so it would incorrectly print dogs.
It was a rough example but the idea is thinking in terms of data in and data out and how can it be done. Here the train of thought first would be: do I have the right data form for the thing I am doing? Here we have: {company: {staff: [{..., pets: []}]}} And what we want to do is to produce a list of all the pet cats with its owner name. [{cat: "bla", owner: "bla"}...] or [{owner: "bla", cats:[...],...}, ...] So I gu…
In javascript:
const stf = [
{name: "x", pets: [{type: "cat", name: "kitty"},
{type: "cat", name: "kitty2"}]},
{name: "y", pets: [{type: "dog"}]},
{name: "z", pets: [{type: "cat", name: "miau"}]},
];
const myTransform = ({ pets, name: ownerName }) => pets
.filter(({type}) => type === "cat")
.map(({ name: catName }) => ({ ownerName, catName }))
stf
.map(myTransform)
.flat()
.forEach(({ownerName, catName}) => console.log(`Cat ${catName} to ${ownerName}`))