propDrilling.ts

type NativeType = null | number | string | boolean | symbol | Function;
type InferDefault<P, T> = ((props: P) => T & {}) | (T extends NativeType ? T : never);

function getDefault<P, K extends keyof P>(defaults: DefaultProps<P>, k: K, injected?: DefaultProps<P>): InferDefault<P, P[K]> | undefined {
    return (p) => {
        const t: InferDefault<P, P[K]> | undefined = (injected && k in injected) ? injected[k] : defaults[k]
        if (typeof t === 'function') return t(p)
        return t
    }
}

export function makeInjectDefaults<T, K extends string = 'fs'>(defaults: DefaultProps<T>, key: K = 'fs' as K) {
    const injectionKey: InjectionKey<DefaultProps<T>> = Symbol(`${key}-vue-props`)

    //const provideFun =
    return () => ({
        [`provide${key}Props`]: (v: DefaultProps<T>, injectBase = true) => {
            console.log(`provide${key}Props`, v)
            if (injectBase) {
                const injected = inject(injectionKey)
                provide(injectionKey, Object.assign({}, injected, v))
                //console.log(`provide${key}Props injected`, Object.assign({}, injected, v))
            } else provide(injectionKey, v)
        },
        [`getInjected${key}Defaults`]: () => {
            const injected = inject(injectionKey)
            console.log(`getInjected${key}Defaults`, injected)
            return Object.fromEntries(
                Object.keys(defaults)
                    .map(k => ([k, getDefault(defaults, k as keyof T, injected)]))
            ) as DefaultProps<T>
        }
    } as Record<`provide${K}Props`, (v: DefaultProps<T>, injectBase?: boolean) => void> & Record<`getInjected${K}Defaults`, () => DefaultProps<T>>)
}