A TypeScript type that will dynamically knows every nested object property. specially helpful when being used on a dynamic size object you want to access.

shape-of-type.ts

type ShapeOf<T extends Record<string, any>> = keyof {
    [K in keyof T as T[K] extends string ? K: T[K] extends Record<string, unknown> ? `${K & string}.${ShapeOf<T[K]> & string}` : never]: any
}

const locales = {
    en: {
        welcome: 'welcome',
        job: {
            title: 'Job title',
            description: 'Job description'
        },
        footer: {
            left: 'sample footer left',
            right: {
                top: 'sample footer right'
            }
        }
    }
}

type LocaleMap = typeof locales

type LocaleName = keyof LocaleMap

type Locale = LocaleMap[LocaleName]

let currentLocale: LocaleName = 'en'



function get(object: Record<string, unknown>, path: Array<string>, index = 0): string {
    const key = path[index]
    if(key === undefined) {
        return ''
    }
    const result = object[key]
    if(result === undefined) {
        return ''
    }

    if(typeof result === 'string') {
        return result;
    }

    return get(Object(result), path, index + 1)
}

export function t(key: ShapeOf<Locale>) {
    return get(locales[currentLocale], key.split('.'))
}


t("footer.right.top")