Querying optional local fields by graphql - graphql

Question

With GraphQL, I like to query an entire array with all the fields that are found in only some of the array elements.
Assume I have the following data and local client:
// data1.json
[
{
"type": "title",
"description": "Title!"
},
{
"type": "person",
"description": "He has been working in this office for 10 years."
"name": "Thomas"
"age": "35"
},
{
"type": "office",
"description": "Engineering"
"size": "90"
"budget": "1500000"
},
]
import data1 from './data1.json'
import data2 from './data2.json' // same structure to data1
... // other imports
const client = new ApolloClient({
cache: new InMemoryCache()
});
client.cache.writeData({
data: {
departments: [
{
name: 'departmentOne',
data: data1.map(item => ({ ...item, __typename: 'element' })),
__typename: 'department'
},
{
name: 'departmentTwo',
data: data2.map(item => ({ ...item, __typename: 'element' })),
__typename: 'department'
}
],
__typename: 'departments'
}
});
Then, in one of my component, how do I get all the elements in the departments?
When I query this it just works:
{
departments #client {
name
data {
type
description
__typename
}
__typename
}
}
But the following query will return nothing:
{
departments #client {
name
data {
type
description
name
age
size
budget
__typename
}
__typename
}
}
I suppose I need to add a local resolver or typeDefs for this purpose, but how would it look like?
In the first place, I am not sure if the cache has all the array. As some of the fields (i.e., "name", "age", and others) are missing in some element, might it omit the data automatically?