# Encodable incorrect Json string with URL and Decimal existentials

**URL:** <https://forums.swift.org/t/encodable-incorrect-json-string-with-url-and-decimal-existentials/68713>\
**Category:** Using Swift\
**Created:** [November 29, 2023, 5:54pm UTC](https://forums.swift.org/t/encodable-incorrect-json-string-with-url-and-decimal-existentials/68713 "2023-11-29T17:54:05Z")\
**Posts on this page:** 1\
**Showing post:** 1

<div class="post-metadata">

**Author:** ![Dmitriy\_Ignatyev](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/dmitriy_ignatyev/32/11340_2.png) [@Dmitriy\_Ignatyev](https://forums.swift.org/u/Dmitriy_Ignatyev)\
**Post date:** [November 29, 2023, 5:54pm UTC](https://forums.swift.org/t/encodable-incorrect-json-string-with-url-and-decimal-existentials/68713/1 "2023-11-29T17:54:06Z")

</div>

Hi. I've met weird behavior trying to encode URL and Decimal values as existentials. When instances of these types are wrapped as `any Encodable` the result JSON string is incorrect.

Here is the minimal code for playground to reproduce:

```swift
let url = URL(string: "www.apple.com")!
let decimal = Decimal(string: "10.1")!

let urlJsonString: String // ok, == "www.apple.com"
let decimalJsonString: String // ok, == "10.1"
do {
  let encoder = JSONEncoder()
  
  let urlData = try! encoder.encode(url)
  let decimalData = try! encoder.encode(decimal)
  
  urlJsonString = String(decoding: urlData, as: UTF8.self)
  decimalJsonString = String(decoding: decimalData, as: UTF8.self)
}

let urlJsonStringAny: String // invalid, == "{"relative":"www.apple.com"}"
let decimalJsonStringAny: String // invalid, == "{"exponent":-1,"length":1,"isCompact":true,"isNegative":false,"mantissa":[101,0,0,0,0,0,0,0]}"
do {
  let encoder = JSONEncoder()
  
  let urlData = try! encoder.encode(AnyEncodable(url as any Encodable))
  let decimalData = try! encoder.encode(AnyEncodable(decimal as any Encodable))
  
  urlJsonStringAny = String(decoding: urlData, as: UTF8.self)
  decimalJsonStringAny = String(decoding: decimalData, as: UTF8.self)
}

public struct AnyEncodable: Encodable {
  private let encodable: any Encodable

  public init(_ encodable: any Encodable) {
    self.encodable = encodable
  }

  public func encode(to encoder: any Encoder) throws {
    try encodable.encode(to: encoder)
  }
}

```

Existential values give "{"relative":"[www.apple.com](http://www.apple.com)"}" for url instance and "{"exponent":-1,"length":1,"isCompact":true,"isNegative":false,"mantissa":[101,0,0,0,0,0,0,0]}" for decimal instance.

Seems it is a bug, but may be I'm missing something.

---

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