Type Path returns all possible variants of the key for the function lodash.get

path.ts

type ValueOf<T> = T[keyof T];

type ArrayPath<T> =
  T extends Array<unknown>
    ? ArrayPath<Omit<T, keyof []>>
    : T extends object
      ? ValueOf<{
        [K in keyof T]: [K] | [K, ...ArrayPath<T[K]>];
      }>
      : never;

type StringPath<T> =
  T extends [...infer A, infer K]
    ? K extends string | number
    ? A extends void[]
      ? K
      : `${StringPath<A>}${PathVariants<K>}`
    : never
    : never;

type PathVariants<K extends string | number> =
  | DotStringPathVariants<K | ArrayStringPathVariants<K>>
  | ArrayStringPathVariants<K>;

type DotStringPathVariants<K extends string | number> = `.${K}`;

type ArrayStringPathVariants<K extends string | number> = `[${K}]` | `['${K}']` | `["${K}"]`;

export type Path<T> = ArrayPath<T> | StringPath<ArrayPath<T>>;