PUT request using Fetch

[lorenalexm]

I am trying to figure out how to use JSObject.global.fetch.function! along with JSPromise to assemble a PUT request with a body and headers. I keep falling flat on my face 😣 I am able to use fetch and preform GET requests, parse the JSON, and the whole-nine-yards, but I don't understand where to go for sending data.

I have tried assembling a params object using something like this JSObject.construct(from: ["method": "PUT", "body": json.jsString].jsValue) and passing it as a second parameter to fetch. Doing this though, when handling the .then statement I receive an error of:

/Users/lorenalexm/Projects/SwiftScheduleCheck/Sources/SwiftScheduleCheck/Views/ContentView.swift:118:16: Cannot convert value of type '()' to closure result type 'ConvertibleToJSValue'

Might anyone help provide a bit of guidance on how to proceed from here? Thank you!

[MaxDesiatov]

Here's a snippet for posterity, note that it's slightly inconsistent with the use of Codable due to #116:

import Foundation
import JavaScriptEventLoop
import JavaScriptKit

JavaScriptEventLoop.installGlobalExecutor()

struct Body: Codable {
  let x: Int
  let y: String
}

private let jsFetch = JSObject.global.fetch.function!
func fetch(_ url: String, _ options: [String: JSValue]) async throws -> JSValue {
  try await JSPromise(jsFetch(url, options).object!)!.value
}

let encoder = JSONEncoder()
let decoder = JSValueDecoder()

func post<Body: Codable>(_ url: String, _ body: Body) async throws -> Body {
  let data = try encoder.encode(body)
  let response = try await fetch(
    url,
    [
      "method": "POST",
      "headers": ["Content-Type": "application/json"].jsValue,
      "redirect": "follow",
      "body": String(data: data, encoding: .utf8)!.jsValue,
    ]
  ).object!
  let json = try await JSPromise(response.json!().object!)!.value
  return try decoder.decode(Body.self, from: json.object!.json)
}

Also note the use of json.object!.json, it's a peculiarity of httpbin, which I used to test this. It wraps the response in a top-level JSON structure, having body in the inner json property. You may need to use json instance directly with other services instead.

@lorenalexm does that resolve your issue?

[lorenalexm]

@MaxDesiatov I am so sorry for the delay in replying. Thank you so much for the explanation and code snippet, this really helped me work through my issue and build a reusable class for making network requests in my Tokamak projects! Your assistance has helped resolve my problems, thank you again.