Cannot set HTMLElement.style properties about javascriptkit HOT 2 OPEN

This is a limitation of the current API design of JavaScriptKit.
spanElem.style.backgroundColor = "yellow" is evaluated as below:

var style = spanElem.style
style.backgroundColor = "yellow"
spanElem.style = style

Even style is a reference type in JavaScript world, it's expressed by value type in Swift, so spanElem.style = style re-assignment is appeared. But this assignment causes undefined behavior because HTMLElement.style is readonly property and it clears all CSS attributes.

I'll re-design JavaScriptKit API to resolve this semantics mismatch, but please use this workaround to avoid re-assignment for a while. Sorry.

import JavaScriptKit

let document = JSObject.global.document

var spanElem = document.createElement("span")
spanElem.innerText = "hello"
var style  = spanElem.style as JSValue
style.backgroundColor = "yellow"

_ = document.body.appendChild(spanElem)

from javascriptkit.

Thank you for your very helpful response! With it I'm no longer stuck and can continue with my project. :) One note:

I'll re-design JavaScriptKit API to resolve this semantics mismatch, but please use this workaround to avoid re-assignment for a while. Sorry.

var style  = spanElem.style

I had to write spanElem.style as JSValue because I would otherwise get the following error:

[...]/main.swift:7:14: error: ambiguous use of 'subscript(dynamicMember:)'
var style  = spanElem.style

This problem pops up here and there. Maybe a re-design could also alleviate this small annoyance? If there's already a document or issue use to gather such input I'd be happy to contribute this observation (and some others) there!

from javascriptkit.