main.swift

import JavaScriptKit

let alert = JSObject.global.alert.function!
let document = JSObject.global.document

print("Hello from WASM, document title: \(document.title.string ?? "")")

var count = 0

var divElement = document.createElement("div")
divElement.innerText = .string("Count \(count)")
_ = document.body.appendChild(divElement)

var clickMeElement = document.createElement("button")
clickMeElement.innerText = "Click me"
clickMeElement.onclick = JSValue.object(
    JSClosure { _ in
        count += 1
        divElement.innerText = .string("Count \(count)")
        return .undefined
    }
)
_ = document.body.appendChild(clickMeElement)

var encodeResultElement = document.createElement("pre")
var textInputElement = document.createElement("input")
textInputElement.type = "text"
textInputElement.placeholder = "Enter text to encode to UTF-8"
textInputElement.oninput = JSValue.object(
    JSClosure { _ in
        let textEncoder = JSObject.global.TextEncoder.function!.new()
        let encode = textEncoder.encode.function!
        let encodedData = JSTypedArray<UInt8>(
            unsafelyWrapping: encode(this: textEncoder, textInputElement.value).object!
        )
        encodeResultElement.innerText = .string(
            encodedData.withUnsafeBytes { bytes in
                bytes.map { hex($0) }.joined(separator: " ")
            }
        )
        return .undefined
    }
)
let encoderContainer = document.createElement("div")
_ = encoderContainer.appendChild(textInputElement)
_ = encoderContainer.appendChild(encodeResultElement)
_ = document.body.appendChild(encoderContainer)

func print(_ message: String) {
    _ = JSObject.global.console.log(message)
}

func hex(_ value: UInt8) -> String {
    var result = "0x"
    let hexChars: [Character] = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"]
    result.append(hexChars[Int(value / 16)])
    result.append(hexChars[Int(value % 16)])
    return result
}