feat(jex): extension check returns a reason on failure

[franklevasseur]

Example 1:

undefined ⊆ number ?
 - #: undefined ⊈ number

{a: string | undefined} ⊆ {a: string} ?
 - #.a: undefined ⊈ string

string | number | undefined | null ⊆ string | number ?
 - #: undefined ⊈ string
 - #: undefined ⊈ number
 - #: null ⊈ string
 - #: null ⊈ number

string ⊆ "banana" ?
 - #: string ⊈ "banana"

"banana" ⊆ number | "apple" ?
 - #: "banana" ⊈ number
 - #: "banana" ⊈ "apple"

string[] ⊆ number[] ?
 - #[number]: string ⊈ number

[string, number] ⊆ number[] ?
 - #[0]: string ⊈ number

Record<string, string | undefined | boolean> ⊆ Record<string, string> ?
 - #[string]: undefined ⊈ string
 - #[string]: boolean ⊈ string

Example 2:

import zodToJsonSchema from 'zod-to-json-schema'
import * as z from 'zod'
import * as jex from './src'
import { JSONSchema7 } from 'json-schema'

const z2j = (...args: Parameters<typeof zodToJsonSchema>) => zodToJsonSchema(...args) as JSONSchema7

const typeA = z2j(
  z.object({
    a: z.string(),
    b: z.tuple([
      z.any(),
      z.object({
        c: z.record(z.union([z.tuple([z.string(), z.number()]), z.object({ d: z.string() }), z.literal('e')]))
      })
    ])
  })
)

const typeB = z2j(
  z.object({
    a: z.string(),
    b: z.tuple([
      z.any(),
      z.object({
        c: z.record(z.union([z.tuple([z.string(), z.number()]), z.object({ d: z.string() })]))
      })
    ])
  })
)

jex.jsonSchemaExtends(typeA, typeB).then((extension) => console.log(extension))

// logs:
{
  extends: false,
  reasons: [
    '#.b[1].c[string]: "e" ⊈ [string, number]',
    '#.b[1].c[string]: "e" ⊈ { d: string }'
  ]
}