Customizing quicktype... simpler case (type substitution + generated properties)

[FFdhorkin]

The only existing examples for customizing quicktype are a bit overwhelming, especially if your use case is much simpler. For more simple substitutions, is there a better way?

Currently, my schema input matches this type definition:

type RawSchema = {
    [key: string]: RawSchema | null;
};
// for brevity, I've created some aliases:
type SomeType = Cypress.Chainable<JQuery<HTMLElement>>;
type SomeOtherType<T> = (text: string) => T & Cypress.Chainable<JQuery<HTMLElement>>;

I am running quicktype algorithmically. In the interface output, anywhere the schema had null, I want to replace that with SomeType

For this first part, I could do this, but it feels hacky:

const final = await quicktype({...});
final.lines = final.lines.map(row => row.replace(/null;$/, 'SomeType;'));

Additionally, when there's a rows.row.x property, I want to modify the output to insert an extra with property, which contains the same keys as rows.row but different types. (Basically, for any x in rows.row.x, I want to output a rows.with.x with type (text: string) => SomeOtherType<SomeRowType >)

For example, I would like this:

{
    "apple": {
        "banana": { 
              "rows": {
                    "row": {
                          "name": null,
                          "id": null
                    }
              },
              "cherry": null
         },
         "durian": null
    }
}

to output something along these lines:

export interface TopLevel {
    apple: Apple;
}

export interface Apple {
    banana: Banana;
    durian: SomeType;
}

export interface Banana {
    rows:      Rows;
    cherry:    SomeType;
}

export interface Rows {
    row: RowClass;
    with: WithClass;
}

export interface RowClass {
    name: SomeType;
    id:   SomeType;
}

export interface WithClass {
    name: (text: string) => RowClass & SomeOtherType;
    id:   (text: string) => RowClass & SomeOtherType;
}

The net goal is that both topLevel.apple.banana.rows.row.name and topLevel.apple.banana.rows.with.name('foo').id would both be valid for IntelliSense.

Additionally, since there are multiple keys with row as name, the generated interfaces end up with weird/arbitrary names like PurpleRow and FluffyRow as opposed to something like BananaRow. I'd like to use the parent interface name as a prefix rather than a random string.

The aforementioned customization example shows how to override inheritance and set default properties, but it's a fairly complex example that doesn't even match my use case. Unfortunately, I haven't been able to figure out which functions I need to override to get this behavior. Closest guess I've had thus far is overriding emitPropertyTable or sourceFor, or maybe emitClassBlockBody. That's as far as I've managed, though.

Thank you!