type SomeType = {
    key1: string;
    key2: number;
    key3: boolean;
}

export type MySpecialObject = {
    theThingIWantToUpdate: SomeType;
    // with other keys and stuff
}

export type MyContextStateType = {
    myValue: SomeOtherType;
    myArray: MySpecialObject[];
}

export type MyContextType = {
    myContext: Store<MyContextStateType>;
    pushObjectToMyArray: (myObject: MySpecialObject) => void;
    setObjectAtIndex: (myObject: MySpecialObject, index: number) => void;
    setAttributeAtIndex: (key: keyof MySpecialObject, value: any, index: number) => void;
    etc;
}

export function MyContextProvider() {
    const [myValue] = createResource(myValueId, myValueFetcher);
    let myContext: MyContextType = undefined;
    const [isReady, setIsReady] = createSignal<boolean>(false);

    createMemo(async () =>{
        if (myValue() && !myContext) {
            myContext = await initMyContext(myValue);
            setIsReady(true);
        }
    });

    return (<Show when=blablabla>
        <MyContext.Provider value={myContext}>
            {props.children}
        </MyContext.Provider>
    </Show>
    );
}

export const initMyContext = (myValue: SomeOtherType) => {
    const [myContext, setMyContext] = createStore<MyContextStateType>({
        myValue: myValue,
        myArray: []
    });

    // do stuff to initialize

    return {
        myContext: myContext,
        pushObjectToMyArray: (myObject: MySpecialObject) => {
            setMyContext('myArray', (arr: MySpecialObject[]) => [
                ...arr,
                { ...myObject }
            ]);
        },
        setObjectAtIndex: (myObject: MySpecialObject, index: number) => {
            setMyContext('myArray', index, { ...myObject });
        },
        setAttributeAtIndex: (key: keyof MySpecialObject, value: any, index: number) => {
            setMyContext(
                'myArray',
                index,
                'theThingIWantToUpdate',
                key,
                value
            );
        }
    }
}