ValidPath

Since 1.1.0

Check if a path exists in a type.

Signature

type ValidPath<T, P extends string> = T extends Primitive
  ? P extends ''
    ? true
    : false
  : P extends ''
    ? true
    : P extends `${infer K}.${infer Rest}`
      ? K extends keyof T
        ? ValidPath<T[K], Rest>
        : false
      : P extends keyof T
        ? true
        : false

Parameters

Parameter	Description
T	The object type
P	The path to check

Description

Returns true if the path exists in the type, false otherwise.

Examples

Basic Usage

import type { ValidPath } from 'uni-types'

interface Obj {
  a: {
    b: string
    c: {
      d: number
    }
  }
}

type Path1 = ValidPath<Obj, 'a.b'>    // true
type Path2 = ValidPath<Obj, 'a.c.d'>  // true
type Path3 = ValidPath<Obj, 'a.x'>    // false
type Path4 = ValidPath<Obj, ''>       // true (root)

Conditional Types

type SafePath<T, P extends string> = ValidPath<T, P> extends true
  ? P
  : never

Related

• PathLength - Get path segment count
• DeepPick - Pick nested properties