deep-stub-object

!Libraries.io dependency status for latest release

Proxy-backed custom error message instead of TypeError: x is undefined

Getting started

$ npm i deep-stub-object

Reference

``typescript
export type DeepPartial = T extends Record
? {
readonly [P in keyof T]?: DeepPartial
}
: T

export type DeepRequired = T extends Record
? {
readonly [P in keyof T]-?: DeepRequired
}
: T

type Func

= (...args: P) => R

type Nested = Func | { readonly [prop: string]: Nested }

export function deepStub(
target: DeepPartial | undefined,
message: (path: readonly string[]) => string
): DeepRequired
`

Usage

`typescript
import 'ts-jest'
import { deepStub, DeepPartial } from 'deep-stub-object'

type Obj = {
x: () => 1
y: { x: () => 'test' }
z: { y: { x: () => true } }
}

const deepStubObj = (obj?: DeepPartial) => deepStub(obj, (path) => path.join('.'))

describe('index', () => {
test('deepStub - throw', () => {
const stub = deepStubObj()

expect(() => stub.x()).toThrowError('x')
expect(() => stub.y.x()).toThrowError('y.x')
expect(() => stub.z.y.x()).toThrowError('z.y.x')
})

test('deepStub - no throw', () => {
const stub = deepStubObj({ x: () => 1, z: { y: { x: () => true } } })

expect(stub.x()).toEqual(1)
expect(stub.z.y.x()).toEqual(true)
})
})
``