Tested in both FF 83 and Chromium 86 with the following Go environment:

GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/smoyer1/.cache/go-build"
GOENV="/home/smoyer1/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/smoyer1/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/smoyer1/go:/usr/share/go-tools"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/opt/go/1.15.4"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/go/1.15.4/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/smoyer1/git/hnjobs/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build286617590=/tmp/go-build -gno-record-gcc-switches"

Compiled with:

RUN GOOS=js GOARCH=wasm go build -o /app cmd/ui/ui.go

The console provides the following call stack when the button is clicked:

panic: ValueOf: invalid value wasm_exec.js:50:14
<empty string> wasm_exec.js:50:14
goroutine 6 [running]: wasm_exec.js:50:14
syscall/js.ValueOf(0x1e5e0, 0x5ab88, 0x6, 0x7ff800010000000f) wasm_exec.js:50:14
	/usr/local/go/src/syscall/js/js.go:219 +0x106 wasm_exec.js:50:14
syscall/js.Value.Set(0x7ff8000100000012, 0x41a078, 0x52ef6, 0x6, 0x1e5e0, 0x5ab88) wasm_exec.js:50:14
	/usr/local/go/src/syscall/js/js.go:314 +0x7 wasm_exec.js:50:14
syscall/js.handleEvent() wasm_exec.js:50:14
	/usr/local/go/src/syscall/js/func.go:97 +0x25

I'd be happy to help track this down ... it appears that the JS value passed to the syscall/js ValueOf() function is perhaps a wrapped type and doesn't match any of the types in the case statement included there (see https://github.com/golang/go/blob/0e953add9656c32a788e06438cd7b533e968b7f8/src/syscall/js/js.go#L162). I've looked through the webapi code and all the JS values appear to (properly) be aliases which I would expect to match a case, so I'm at a loss for where to continue looking.

It's currently broken (at least partially) for current version of Go. I have a fixing PR since March, that has not been approved/responded: https://github.com/gowebapi/webapi/pull/11

I'm happy to help support, if you add me as a member of gowebapi.

cheers

I'm very happy to find your project here. I was just about to try and write myself a WebIDL parser to do exactly this, so well done and thanks.

Anyway I'm not sure the best way to provide feedback? Basically I'm wanting to do some WebGL (v1) via Go/WASM, and hopefully from that also include WebVR support. I can see that you have WebXR support, but there are not many browsers supporting that so far. Do you have any plans to add WebVR?

So far I managed to get my Go WASM creating a 'canvas' element:

	canvas := webapi.GetWindow().Document().CreateElement("canvas", &webapi.Union{js.ValueOf("dom.Node")})
	canvas.SetId("mycanvas")
app.AppendChild(&canvas.Node)

And finally, I can see that you have some full screen support in dom.go, but I cant see a method to requestFullscreen() or am I missing something obvious there?

Sorry to ask so many questions, and keep up the good work!

macos10.12.4 go1.12

Because of performance reasons Go is dropping js.Wrapper. I noticed this today, as I was trying out the 1.18.1 beta.

I suspect it should be an easy fix, but I haven't yet dived into it. Hopefully the fix will be backwards compatible -- since it only removed functionality.

I'll try to do post benchmarking in a wasm game I occasionally develop.

After the go 1.14 update the file dom/helper.go was failing to compile for wasm (it would still compiles if not wasm). the underlying syscall/js Value type must have changed, is my guess.

But in any case, it now offers the safer IsUndefined() method. So I added it to the core/js/js.go wrappers and changed helper.go to use it.

Error trying to build using Go v1.13:

"/go/src/github.com/gowebapi/webapi/core/js/js_js.go:56:19: undefined: js.TypedArray"

I commented out the references to this type in your code to get it building. Is that appropriate?

Functions that get a pointer to a string/int/bool should dereference the pointers before passing them to any js functions

For example

// SetTextContent setting attribute 'textContent' with
// type string (idl: DOMString).
func (_this *Node) SetTextContent(value *string) {
	input := value
	_this.Value_JS.Set("textContent", input)
}

could be

// SetTextContent setting attribute 'textContent' with
// type string (idl: DOMString).
func (_this *Node) SetTextContent(value *string) {
	if value != nil {
		input := *value
		_this.Value_JS.Set("textContent", input)
	}
}

otherwise it panics panic: ValueOf: invalid value

Similar,

func (_this *Node) CloneNode(deep *bool) (_result *Node) {
	var (
		_args [1]interface{}
		_end  int
	)
	if deep != nil {
		_p0 := deep
		_args[0] = _p0
		_end++
	}
	_returned := _this.Value_JS.Call("cloneNode", _args[0:_end]...)
	var (
		_converted *Node // javascript: Node _what_return_name
	)
	_converted = NodeFromJS(_returned)
	_result = _converted
	return
}

could be

func (_this *Node) CloneNode(deep *bool) (_result *Node) {
	var (
		_args [1]interface{}
		_end  int
	)
	if deep != nil {
		_p0 := *deep
		_args[0] = _p0
		_end++
	}
	_returned := _this.Value_JS.Call("cloneNode", _args[0:_end]...)
	var (
		_converted *Node // javascript: Node _what_return_name
	)
	_converted = NodeFromJS(_returned)
	_result = _converted
	return
}

Would you mind to create an example how to use indexeddb? I managed to open a db request but have no clue to get db instance from event like below. request := webapi.GetWindow().IndexedDB().Open("test", nil) request.SetOnupgradeneeded(domcore.EventHandlerToJS(func(event *domcore.Event) interface{} { /* javascript version is: var db = event.target.result; var objStore = db.createObjectStore("names", { autoIncrement : true }); */ return nil })) `

A typical pattern in WebGL is to bind a "null" value.

E.g.

gl.bindFramebuffer(gl.FRAMEBUFFER, null);

According to the documentation, this is how to reset the current FBO back to the canvas:

framebuffer A WebGLFramebuffer object to bind, or null for binding the Canvas or OffscreenCanvas object associated with the rendering context.

Because of how the types are implemented in WebGL, this is not elegant to do

Preferred pattern:

gl.BindFramebuffer(webgl.FRAMEBUFFER, webgl.FramebufferFromJS(js.Null()))

Unfortunately this will panic

Problem

From webgl_js.go:

// FramebufferFromJS is casting a js.Value into Framebuffer.
func FramebufferFromJS(value js.Value) *Framebuffer {
	if typ := value.Type(); typ == js.TypeNull || typ == js.TypeUndefined {
		return nil
	}
	ret := &Framebuffer{}
	ret.Value_JS = value
	return ret
}

In the case of js.Null() this returns a nil pointer, which we try to pass to BindFramebuffer

func (_this *RenderingContext) BindFramebuffer(target uint, framebuffer *Framebuffer) {
	var (
		_args [2]interface{}
		_end  int
	)
	_p0 := target
	_args[0] = _p0
	_end++
	_p1 := framebuffer.JSValue()
	_args[1] = _p1
	_end++
	_this.Value_JS.Call("bindFramebuffer", _args[0:_end]...)
	return
}

Unfortunately, this code expected a non-nil Framebuffer, and will panic

Workaround

It's possible to work around it by manually creating the Framebuffer object, but it's not elegant:

nullFBO := &webgl.Framebuffer{Object: webgl.Object{
	Value_JS: js.Null(),
}}
gl.BindFramebuffer(webgl.FRAMEBUFFER, nullFBO)

Solutions

I can think of a couple of solutions:

1. Simple remove the IsNull check from the *FromJS methods and allow the creation of null objects. gl.BindFramebuffer(webgl.FRAMEBUFFER, webgl.FramebufferFromJS(js.Null()))
2. Create global Null versions of objects. gl.BindFramebuffer(webgl.FRAMEBUFFER, webgl.NullFramebuffer)
3. Change the bind methods and convert nil to js.Null gl.BindFramebuffer(webgl.FRAMEBUFFER, nil)

Notes

From my OpenGL understanding this pattern is used for all objects. I.e. all Bind* and Use* methods (gl.bindTexture/gl.useProgram/gl.bindBuffer etc)

The mozdev webgl documentation is unfortunately a little lacking, and only framebuffers are explicitly mentioned to be null - but I assume it also holds true for any other objects

Great project 👍 Wasm is the future of webdev and go is an awesome langage.

Could be interesting to add a chapter in the readme file with examples of projects using this webapi in go. The syntax to call some html / js is not trivial.

For all purpose, I'm currently working on an HTML5 interactive chart, 100% in go, based on canvas and wasm via this webapi: https://github.com/sunraylab/gowebstockchart

Thank You for this awesome project..

I dont see https://developer.mozilla.org/en-US/docs/Web/API/WebCodecs_API in the code generated golang.

Here is what i am up to:

I want to make a Video player using golang wasm, and customise how the player looks and feels using GIO ( https://github.com/gioui) Gio can compile to web, desktop and mobile.

The WebCodecs_API will allow me to build a custom player feeding the frames into it.

Then i am thinking of using a webview for Desktop and Mobile using https://github.com/Inkeliz/gowebview, so that it also works on those targets.

Please let me know if you have support for the webCodecs...