Validating optional fields within optional fields within arrays fails incorrectly

[jeshuamaxey]

This is really hard to explain in words, but the reproduction should help explain. If you are validating an array of objects and those objects have optional properties which themselves have optional properties, the validation fails to take into account the optionality of the nested fields.

reproduction

import { expect } from "chai"
import chaiJsonPattern from "chai-json-pattern"

describe.only("failing check against arrays of objects with optional fields which have optional sub fields", () => {
  const jsonPattern = `{
    "data": [{
      "id": String,
      
      "optional_object"?: {
        "required_string_field": String,
        "optional_string_field"?: String,

        "optional_sub_object"?: {
          "required_string_field": String,
          "optional_string_field"?: String,
        }
      }
    }]
  }`

  describe("without optional sub object", () => {
    it("should pass when array contains element with optional object ", () => {
      expect({
        data: [
          {
            id: "1",
          },
        ],
      }).to.matchPattern(jsonPattern)
    })

    it("should pass when array contains element without optional object", () => {
      expect({
        data: [
          {
            id: "1",
            optional_object: {
              required_string_field: "1",
              optional_string_field: "1",
            },
          },
        ],
      }).to.matchPattern(jsonPattern)
    })

    it("should pass when array contains elements with and without optional object", () => {
      expect({
        data: [
          {
            id: "1",
            optional_object: {
              required_string_field: "1",
              optional_string_field: "1",
            },
          },
          {
            id: "1",
          },
        ],
      }).to.matchPattern(jsonPattern)
    })
  })

  describe("with optional sub object", () => {
    it("should pass when array contains element with optional object with optional sub object", () => {
      expect({
        data: [
          {
            id: "1",
            optional_object: {
              required_string_field: "1",
              optional_string_field: "1",
              optional_sub_object: {
                required_string_field: "1",
                optional_string_field: "1",
              },
            },
          },
        ],
      }).to.matchPattern(jsonPattern)
    })

    it("should pass when array contains 2 elements with optional object, where one contains the optional sub object and the other doesn't", () => {
      expect({
        data: [
          {
            id: "1",
            optional_object: {
              required_string_field: "1",
              optional_string_field: "1",
            },
          },
          {
            id: "1",
            optional_object: {
              required_string_field: "1",
              optional_string_field: "1",
              optional_sub_object: {
                required_string_field: "1",
                optional_string_field: "1",
              },
            },
          },
        ],
      }).to.matchPattern(jsonPattern)
    })
  })
})