A package to build progressive web apps with Go programming language and WebAssembly.



Circle CI Go build Go Report Card GitHub release pkg.go.dev docs Twitter URL

Go-app is a package for building progressive web apps (PWA) with the Go programming language (Golang) and WebAssembly (Wasm).

Shaping a UI is done by using a declarative syntax that creates and compose HTML elements only by using the Go programing language.

It uses Go HTTP standard model.

An app created with go-app can out of the box run in its own window, supports offline mode, and are SEO friendly.


go-app documentation


go-app requirements:

go mod init
go get -u github.com/maxence-charriere/go-app/v8/pkg/app

Declarative syntax

Go-app uses a declarative syntax so you can write reusable component-based UI elements just by using the Go programming language.

Here is a Hello World component that takes an input and displays its value in its title:

type hello struct {

	name string

func (h *hello) Render() app.UI {
	return app.Div().Body(
			app.Text("Hello, "),
			app.If(h.name != "",
				Placeholder("What is your name?").

Standard HTTP

Apps created with go-app complies with Go standard HTTP package interfaces.

func main() {
    // Components routing:
	app.Route("/", &hello{})
	app.Route("/hello", &hello{})

    // HTTP routing:
	http.Handle("/", &app.Handler{
		Name:        "Hello",
		Description: "An Hello World! example",

	if err := http.ListenAndServe(":8000", nil); err != nil {

Getting started

Read the Getting Started document.


Code Contributors

This project exists thanks to all the people who contribute. [Contribute].

Financial Contributors

Become a financial contributor and help us sustain go-app development. [Contribute]



Support this project with your organization. Your logo will show up here with a link to your website. [Contribute]

  • Example crashing right away after go build or go run

    Example crashing right away after go build or go run

    I tried to just go build the example project then execute the binary, but it crashes right after it starts. The weird thing is if I use macpack to build it then it doesn't crash. I'm guessing the app wrapper provides data where the raw build does not.

    Go ENV

    GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/3x/0rnfwj_x1jz2p0gzh_gg7_600000gn/T/go-build912724629=/tmp/go-build -gno-record-gcc-switches -fno-common"

    Crash Output

    INFO  2017/01/30 14:00:47 driver.go:31: driver *mac.Driver is loaded
    INFO  2017/01/30 14:00:47 component.go:62: main.Hello has been registered under the tag Hello
    INFO  2017/01/30 14:00:47 component.go:62: main.AppMainMenu has been registered under the tag AppMainMenu
    INFO  2017/01/30 14:00:47 component.go:62: main.WindowMenu has been registered under the tag WindowMenu
    fatal error: unexpected signal during runtime execution
    [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x7fffb3c24b52]
    runtime stack:
    runtime.throw(0x41a1554, 0x2a)
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/panic.go:566 +0x95
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/sigpanic_unix.go:12 +0x2cc
    goroutine 1 [syscall, locked to thread]:
    runtime.cgocall(0x4141160, 0xc42004df20, 0x0)
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/cgocall.go:131 +0x110 fp=0xc42004def0 sp=0xc42004deb0
    	??:0 +0x41 fp=0xc42004df20 sp=0xc42004def0
    	/Users/euforic/go/src/github.com/murlokswarm/mac/driver.go:56 +0x14 fp=0xc42004df28 sp=0xc42004df20
    	/Users/euforic/go/src/github.com/murlokswarm/app/app.go:43 +0x35 fp=0xc42004df40 sp=0xc42004df28
    	/Users/euforic/go/src/github.com/blevein/play/examples/mac/hello/main.go:31 +0x30 fp=0xc42004df48 sp=0xc42004df40
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/proc.go:183 +0x1f4 fp=0xc42004dfa0 sp=0xc42004df48
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/asm_amd64.s:2086 +0x1 fp=0xc42004dfa8 sp=0xc42004dfa0
    goroutine 17 [syscall, locked to thread]:
    	/usr/local/Cellar/go/1.7.5/libexec/src/runtime/asm_amd64.s:2086 +0x1
    goroutine 5 [chan receive]:
    	/Users/euforic/go/src/github.com/murlokswarm/app/ui.go:11 +0x51
    created by github.com/murlokswarm/app.init.1
    	/Users/euforic/go/src/github.com/murlokswarm/app/ui.go:17 +0x35
    opened by euforic 77
  • v9 Testing/Feedback

    v9 Testing/Feedback

    Hello there,

    I know it is pretty close to the v8 release but I had been working on a new version that removes the need to call Compo.Update() to update what is displayed on the screen.

    Unfortunately, it brings some API changes and since some of you are using this package, I wanted to share that work with you and get some feedback before releasing the new version.


    go get -u -v github.com/maxence-charriere/go-app/v9@3653b5c

    Then replace your imports in your code

    What changed

    • No need to call Update anymore!
    • Compo.Defer() has been removed. Now all Dispatch()/Defer() are done from Context.Dispatch(func(Context))
    • Context.Dispatch(func()) is now Context.Dispatch(func(Context)), and UI elements are always checked before launching Component lifecycle event or HTML event handlers
    • Context has now a Defer(func(Context)) method that launches the given function after a component has been updated. It can be handy to perform action after the display is complete, like scrolling to a given location
    • Context has now an After() function that launches a function on the UI goroutine after the given time without blocking the UI
    • There is a new Component lifecycle event: OnUpdate(Context): it is launched only when a component gets updated by a parent, and should replace a scenario where a Compo.Defer() call was called in a Render() app.UI method
    • Context is now an interface. Fields are now methods:
      • Src => Src()
      • JSSrc => JSSrc()
      • AppUpdateAvailable => AppUpdateAvailable()
      • Page => Page()
    • Context has now a Context.Emit(func()) method that launches the given function and notifies parents to update their state. This should be used when implementing your own event handlers in your components, in order to properly update parent components that set a function to the event handler
    • Context has now method to encrypt and decrypt data
      • Encrypt(v interface{}) ([]byte, error)
      • Decrypt(crypted []byte, v interface{}) error
    • Context has now a method that returns device id: DeviceID() string
    • [EXPERIMENTAL] Changed the API for Stack()

    API design decisions

    • This release focuses mainly on getting the usage of the package more reactive
    • The API is designed to make unrecommended things difficult. A good example would be calling a Context.Dispatch() inside a Render() method
    • With the exception of Handler and JS-related things, everything that you might need is now available from Context. Still thinking about whether I should move Compo.ResizeContent() and Compo.ValueTo in Context though

    Please let me know what you think and where it makes things difficult to solve your problem. I will try to help you solve those and/or iterate to make things better.

    @pojntfx @beanpole135 @ZackaryWelch @mar1n3r0


    help wanted working on it 
    opened by maxence-charriere 41
  • Next: Windows

    Next: Windows

    Hello, some stuff are happening here. I'm writing changes that will bring better support for multi-platform dev. Would like to know what is the next driver you would like to be implement.

    opened by maxence-charriere 39
  • Recaptcha


    Hello. anyone know about getting recaptcha to properly work?

    I have it setup to prompt user with a captcha after they click register like so: https://streamable.com/4if31l

    However whenever the captcha submits the form it completely ignores my form submission handler:

    func (c *register) OnCaptchaComplete(ctx app.Context, e app.Event) {
    	print("Captcha complete")

    here is the snippet for the element

    app.Div().Class("flex justify-center").Body(
    	OnSubmit(c.OnCaptchaComplete, nil).
    	&components.Captcha{Callback: "registerCaptchaCB"}),

    Is there a way to easily prevent the captcha from submitting normally and passing in the response and properly send to my handler with the recaptcha response so I can use the data to build a request to the api?

    I know I can just read the query value for the g-recaptcha-response but is there anyway I can prevent recaptcha from submitting a post / get request to the form action?

    opened by ItsVoltz 31
  • Support for push manager

    Support for push manager

    It would be nice to add subscription bootstrap into page.js (https://github.com/maxence-charriere/app/blob/c5fc1cb2b7861d05ca80284f2e38b1b7c46a69b7/internal/http/page.js)

    And callbacks to goapp.js

    opened by bgokden 28
  • How to make wasm reactive?

    How to make wasm reactive?

    The way Go treats wasm as an application means it runs and exits. This is quite limiting compared to modern JS frameworks with their reactive APIs which allow real-time reactivity on external changes. Is this even possible with the current state of things? Maybe keeping dedicated channels open infinite? This would allow all kind of things from state management stores to webhooks to websockets etc.

    Go takes a different approach, Go treats this as an application, meaning that you start a Go runtime, it runs, then exits and you can’t interact with it. This, coincidentally, is the error message that you’re seeing, our Go application has completed and cleaned up.

    To me this feels more closer to the .NET Console Application than it does to a web application. A web application doesn’t really end, at least, not in the same manner as a process.

    And this leads us to a problem, if we want to be able to call stuff, but the runtime want to shut down, what do we do?


    Here is an example:

    I would like to connect the app to an external state management store and make it re-render on state changes. By the time the state changed the runtime has exited, hence unless there is a channel open to keep it alive it can't react to external events after exit.

    opened by mar1n3r0 27
  • Custom Handler

    Custom Handler

    It would be nice if app made it easier to work with a custom Handler. For cases like #501 , I could implement my own handler and have fine grained control.

    opened by andrewrynhard 24
  • TypeError: WebAssembly: Response has unsupported MIME type 'text/plain; charset=utf-8' expected 'application/wasm'

    TypeError: WebAssembly: Response has unsupported MIME type 'text/plain; charset=utf-8' expected 'application/wasm'

    Getting this error

    TypeError: WebAssembly: Response has unsupported MIME type 'text/plain; charset=utf-8' expected 'application/wasm'
    package ui
    import "github.com/maxence-charriere/go-app/v9/pkg/app"
    type Home struct {
    func (h *Home) Render() app.UI {
    	return app.Html().Body(
    			app.H1().Text("Hello World"),
    package cmd
    import (
    // uiCmd represents the ui command
    var uiCmd = &cobra.Command{
    	Use:   "ui",
    	Short: "",
    	RunE: func(cmd *cobra.Command, args []string) error {
    		app.Route("/", new(ui.Home))
    		http.Handle("/", &app.Handler{
    			Author:       "A name",
    			Description:  "domain.tld is an URL shortener service",
    			LoadingLabel: "Yo! Wait up, it's loading...",
    			Name:         "Some Name",
    			Title:        "domain.tld - shorturl service",
    			Version:      "1",
    		return http.ListenAndServe(":7890", nil)
    func init() {
    opened by idc77 22
  • State management

    State management

    Looking for some broad feedback here.

    I have explored further the idea of implementing component composition also known as slots as described here: https://github.com/maxence-charriere/go-app/issues/434.

    While it definitely works in terms of simply compiling the HTML string the complexity it introduced in maintaining state between the root component and children components brought some questions up.

    The simplicity of using Go structs as state management pattern is very appealing but at the same time easily shows its limitations once the app goes beyond the scope of one page - one component structure. Surely with this pattern we can communicate between pages with HTML5 API storage solutions as long as there is no sensitive data. But as long as we outgrow this pattern in-memory state management becomes inevitable.

    This was an issue which most of JS frontend frameworks faced in their early stages and it evolved in to separate global state management modules and tools like Vuex for example.

    Global state management solves all those problems when scaling from small to enterprise-like apps but comes at a cost with it's own caveats and extra stuff to think about and handle.

    What are your thoughts on this ?

    Do you think this will become a hot topic in the near future as the project evolves or it's beyond the scope of current usage requirements ?

    Do you see the same pattern applied or a different technique Go can make use of to make it possible to scale apps ?

    opened by mar1n3r0 22
  • Implements custom elements with xml namespaces (for SVG)

    Implements custom elements with xml namespaces (for SVG)

    I added namespaces to elements and added a method to create custom tags. The reason is, that I wrote an auto converter that can translate HTML to go-app declarative syntax. While experimenting with it, I found that SVG support was missing. But adding all of the SVG seems to be a lot of work. After making a simple variant for custom elements I realized that this will not work for SVG because those elements need to be in a special namespace. So I added namespace support.

    I think my implementation is quite nice. I added a test and documentation with an example of the usage:

    func SVG(w, h int) app.HTMLCustom {
    	return app.Custom("svg", false, app.SVG).
    		Attr("width", w).Attr("height", h)
    func Circle(cx, cy, r int, stroke string, width int, fill string) app.HTMLCustom {
    	return app.Custom("circle", false, app.SVG).
    		Attr("cx", cx).
    		Attr("cy", cy).
    		Attr("r", r).
    		Attr("stroke", stroke).
    		Attr("stroke-width", width).
    		Attr("fill", fill)
    func (c *Dynamic) Render() app.UI {
    	return SVG(100, 100).Body(
    		Circle(50, 50, 40, "black", 3, "red"),
    		app.Text("Sorry, your browser does not support inline SVG"),

    Of course, it adds the "xmlns" field to every element. But I think this is better than having another interface for SVG.

    I am contemplating if there should be an "xmlns" method instead which sets the namespace for every element. That may be a better solution than adding the namespace to the Custom() method. Maybe I try that too and push a commit that uses this later on.

    EDIT: There is another implementation using an XMLNS() method on the elements instead of the many parameters to Custom(). See below!

    opened by oderwat 21
  • v9.6.0



    • Go requirement bumped to Go v1.18
    • Custom elements (Elem and ElemSelfClosing)
    • Prevent component update
    • Engine optimization that ensure a component update is done once per frame cycle
    • Customizable app-worker.js template
    • Some documentation tweak


    • fix #753
    opened by maxence-charriere 20
  • fix: remove infinite loop in replaceRoot

    fix: remove infinite loop in replaceRoot

    Hi @maxence-charriere

    I ran into infinite loop when tried implementing something like this:

    package main
    import (
    type compo struct {
    func (c *compo) Render() app.UI {
    	return app.Div().Body(new(compoA))
    type compoA struct {
    	isLoading bool
    func (c *compoA) OnNav(app.Context) {
    	c.isLoading = true
    func (c *compoA) Render() app.UI {
    	b := new(compoB)
    	b.IsLoading = c.isLoading
    	return b
    type compoB struct {
    	IsLoading bool
    func (c *compoB) Render() app.UI {
    	return app.If(c.IsLoading, app.Div().Text("is loading")).Else(app.A().Text("is not loading"))
    func main() {
    	app.Route("/", new(compo))
    	http.Handle("/", &app.Handler{
    		Name:        "Hello",
    		Description: "An Hello World! example",
    	if err := http.ListenAndServe(":8000", nil); err != nil {
    opened by TcMits 0
  • Documentation issue in go-app page

    Documentation issue in go-app page

    How do I compose a web page?

    Say I want to have a menu, some element in the html body and an html footer.

    I can't seem to wrap my head around composing components together to form a webpage.

    return app.Head().Body(&Menu{}).Div().Body(app.H1().Text("Welcome"))

    If a component can only render independent of other components, how do we put them together?


    opened by ricardoespsanto 4
  • Component level action trigger global level handler

    Component level action trigger global level handler

    The actionDemo component is used for action handler test only.
    The problem is that both comp1 and comp2 value are changed when the "Inc" button of comp1 is clicked.

    package comp
    import (
    type (
    	actionDemo struct {
    	actionCompo struct {
    		FName string
    		value int
    func (this *actionDemo) Render() app.UI {
    	return app.Div().
    				FName: "comp1",
    				FName: "comp2",
    func (this *actionCompo) OnMount(ctx app.Context) {
    	ctx.Handle("value", func(context app.Context, action app.Action) {
    		this.value += action.Value.(int)
    func (this *actionCompo) Render() app.UI {
    	return app.Div().
    				app.Text(": "),
    				app.Text(fmt.Sprintf("%d", this.value)),
    					OnClick(func(ctx app.Context, e app.Event) {
    						ctx.NewActionWithValue("value", 1)
    					OnClick(func(ctx app.Context, e app.Event) {
    						ctx.NewActionWithValue("value", -1)
    opened by gepengscu 11
  • Sanity check:  go-app as a generic decentralized app framework

    Sanity check: go-app as a generic decentralized app framework

    Hi All and Maxence,

    I'm thinking of using go-app as a layer in a decentralized app. By "decentralized app" I mean browser-side persistence, lateral communications between browsers, and so on -- more details below. I see that @oderwat and @mlctrez are apparently already playing with similar ideas: #789.

    Is this a reasonable use of go-app, given current capabilities and roadmap? As far as I can tell so far, the answer to this is "yes". But I have an entire group of people who will be following along and working with me on this effort, and so am checking in here first before we commit several weeks to a POC.


    I host a working group developing a collaboration platform for other groups and teams. This effort is a spinout from the Nation of Makers community, though not exclusive to nor an official effort of that organization; standard disclaimers apply. So far it's just me and a handful of other folks having weekly video calls to think this through.

    The platform is to be open-source, written in Go, though as I mention in a reddit post, I'm not finding many existing examples of Web3-style apps in Go -- most apps in this space appear to still be javascript, with a little Rust. My guess is that Go/WASM is still too new; the payload size may be a contributing factor.

    I believe go-app might be a good fit for filling this gap.


    If we were to use go-app, we would work with @maxence-charriere and everyone else here to discover and work out any issues that might be lurking with using go-app as a generic-enough framework for decentralized apps, including support of the wishlist items below. Go-app already supports most of this, or at least doesn't get in the way.


    By "Web3-style" I don't mean necessarily defi-related. I do mean the following items, adapted from another reddit post:

    • decentralized to the extent that the app can be served from e.g. github pages and run client-side in WASM, likely using IndexedDB for persistence.
    • able to communicate with other nodes through multiple protocols e.g. websocket, webrtc, nats, etc.
    • able to run the same code "headless" in server-side nodes to provide additional persistence and relays between firewalled clients
    • SEO-friendly enough that googlers can find content rendered on server nodes
    • interoperable with a few javascript libraries (e.g. the tiptap editor)
      • likely a micro-frontend architecture style, with comms via the DOM
    • be future-proofed enough that we don't need to deal with breaking changes in the framework
      • go-app does appear to be using semver -- do I have that right? Have there been any hiccups with breaking changes at non-major release points?

    Thanks All,


    opened by stevegt 14
  • Feature request - cross origin setting for manifest link

    Feature request - cross origin setting for manifest link

    I have a use case where I would like to include credentials ( in my case cookies ) in the manifest request.

    See the gotchas section on this link https://web.dev/add-manifest/#link-manifest

    I've tested this small change locally and it resolves the issue.


    I can submit a PR with the changes but would like some advice:

    • How to configure the setting on and off? Environment variable, app.Handler field, or other?
    • Are there other links ( icon, apple-touch-icon ) that would also need to be considered?
    • Have I missed an obvious way to achieve this without code changes?
    opened by mlctrez 5
  • v9.6.7(Oct 18, 2022)

  • v9.6.4(Aug 29, 2022)


    • Loader label is not forced to be lowercase anymore
    • Proxy resources are now fetched from HTTP when TLS is set in a http.Handler. Thanks @oderwat
    Source code(tar.gz)
    Source code(zip)
  • v9.6.3(Aug 22, 2022)

  • v9.6.2(Aug 22, 2022)

  • v9.6.1(Aug 22, 2022)


    • Go requirement bumped to Go v1.18
    • Custom elements (Elem and ElemSelfClosing)
    • Prevent component update
    • Engine optimization that ensure a component update is done once per frame cycle
    • Wasm progress
    • Customizable app-worker.js template
    • Documentation tweaks


    • @oderwat
    Source code(tar.gz)
    Source code(zip)
  • v9.5.1(May 10, 2022)

  • v9.5.0(May 10, 2022)

  • v9.4.1(Mar 26, 2022)

  • v9.3.0(Dec 27, 2021)

  • v9.2.1(Nov 8, 2021)

  • v9.2.0(Nov 3, 2021)

  • v9.1.2(Oct 25, 2021)

  • v9.1.1(Oct 18, 2021)

  • v9.0.0(Sep 22, 2021)

  • v8.0.4(Jun 20, 2021)

  • v8.0.3(Jun 20, 2021)

  • v8.0.2(Apr 20, 2021)

  • v8.0.1(Mar 30, 2021)

  • v8.0.0(Mar 25, 2021)

  • v7.3.0(Feb 19, 2021)

    A scope can be added to event handler in order to trigger event handler updates.

    In a scenario where we want to remove a element from a list, a solution is to create an EventHandler which got the element id set outside. The event handler returned will always have the same addr, which prevent the package to define that an update should be done on the given element.

    To solve this, a scope has been added to the methods that set EventHandler. Here is the an example:

    type issue499Data struct {
    	ID    int
    	Value string
    type issue499 struct {
    	data []issue499Data
    func newIssue499Data() *issue499 {
    	return &issue499{}
    func (c *issue499) OnMount(app.Context) {
    	c.data = []issue499Data{
    		{11, "one"},
    		{22, "two"},
    		{33, "three"},
    		{44, "four"},
    		{55, "five"},
    		{66, "six"},
    		{77, "sever"},
    		{88, "eight"},
    		{99, "nine"},
    func (c *issue499) Render() app.UI {
    	return app.Div().Body(
    		app.H1().Text("Issue 499"),
    				app.Range(c.data).Slice(func(i int) app.UI {
    					d := c.data[i]
    					return app.Button().
    						ID(fmt.Sprintf("elem-%v", d.ID)).
    						OnClick(c.newListener(d.ID), d.ID). // HERE the element ID is added in order to trigger the handler update since the func pointer returned by newListener is always the same.
    func (c *issue499) newListener(id int) app.EventHandler {
    	return func(app.Context, app.Event) {
    		for i, d := range c.data {
    			if id == d.ID {
    				c.data = append(c.data[:i], c.data[i+1:]...)
    Source code(tar.gz)
    Source code(zip)
  • v7.2.0(Jan 8, 2021)

    Hello there,

    This release brings a way to be notified that that app window size changed within components. It can be done by implementing the Resizer interface:

    type myCompo struct{
    func (c *myCompo) OnAppResize(ctx app.Context) {
        // Handle app resizing.

    It can be quite a handful when building layout components. Shell and Flow has been refactored and now uses this mechanism.

    Source code(tar.gz)
    Source code(zip)
  • v7.1.2(Jan 5, 2021)

  • v7.1.1(Jan 5, 2021)

    Hello, Small patch today:

    • Fixed a bug that prevented _bank navigation for paths within the app host
    • Context now have a variable that reports whether the app has been updated in the background
    Source code(tar.gz)
    Source code(zip)
  • v7.1.0(Jan 4, 2021)

    Hello there,

    This version introduces the Updater interface. It allows a component to be notified that the app has been updated.

    This will allow notifying your users that the app has been updated and modifications are available by reloading the page.

    Check the Lifecycle article in the doc to see how to use it.

    Source code(tar.gz)
    Source code(zip)
  • v7.0.7(Dec 29, 2020)

  • v7.0.6(Nov 26, 2020)

    Hello there. Big update today since this release introduces a dogfooded documentation for the package:

    go-app documentation

    Next to this here are the fixes:

    • Iframe attributes have been added
    • Fixed crash when using Javascript function New and Call with interface{}
    • manifest.json has been renamed manifest.webmanifest in order to follow Google PWA guidelines

    This release also introduces some experimental widgets that are layout related:

    Those widgets are used in the documentation introduced above. Since they are experimental, their API may change.

    Source code(tar.gz)
    Source code(zip)
  • v7.0.5(Aug 25, 2020)


    This version provides the following changes:

    • Fixed a bug where boolean attributes were not updated
    • Min() and Max() HTML element functions now take an interface{} argument rather than string
    Source code(tar.gz)
    Source code(zip)
  • v7.0.4(Aug 12, 2020)


    Here is a small release that brings the following:

    • The handler now proxy an ads.txt file that is located at the root of the static files directory. This allows complying with AdSense requirements.
    • app.Input().Step(v int) has been changed to app.Input().Step(v float64) since step can be a decimal value.
    Source code(tar.gz)
    Source code(zip)
  • v7.0.3(Jul 11, 2020)


    Here is v7.0.3 which introduces the following changes:

    • Fixed bug that did not remove event handlers when components were dismounted
    • Refactored how scripts are loaded in the Handler by using defer attribute
    • Added Iframe missing attributes
    • Generated GitHub pages are now installable with Chrome
    # How to update:
    go get -u github.com/maxence-charriere/go-app/v7
    Source code(tar.gz)
    Source code(zip)
  • v7.0.2(Jun 28, 2020)

    Hello there, I'm thrilled to release version 7 of go-app.

    This version is focused on internal improvements that improve code quality and maintainability. Unfortunately, those improvements bring a few small changes in the API, which is why there is a version bump.

    What is new?

    • Context that is bound to a UI element lifecycle. The context can be used with functions that accept context.Context. Contexts are canceled when the UI element they are bound with is dismounted. It is passed in Mounter and Navigator interfaces, and event handlers.

    • TestMatch: testing api to unit test specific UI element:

      tree := app.Div().Body(
      // Testing root:
      err := app.TestMatch(tree, app.TestUIDescriptor{
          Path:     TestPath(),
          Expected: app.Div(),
      // OK => err == nil
      // Testing h2:
      err := app.TestMatch(tree, app.TestUIDescriptor{
          Path:     TestPath(0),
          Expected: app.H3(),
      // KO => err != nil because we ask h2 to match with h3
      // Testing text from p:
      err = app.TestMatch(tree, app.TestUIDescriptor{
          Path:     TestPath(1, 0),
          Expected: app.Text("bar"),
      // OK => err == nil
    • Support for aria HTML element property: Fix #419

          Aria("foo", "bar").
    • A default logger can be set

    • go-app PWA can now be deployed a GitHub Page with the help of GenerateStaticWebsite function:

      package main
      import (
      func main() {
      	  err := app.GenerateStaticWebsite("DST_DIR", &app.Handler{
      		  Name:      "Github Pages Hello",
      		  Title:     "Github Pages Hello",
      		  Resources: app.GitHubPages("goapp-github-pages"),
      	  if err != nil {
      	  fmt.Println("static website generated")

      It generates files that can directly be dropped into a GitHub repository to serve the PWA. See live example: https://maxence-charriere.github.io/goapp-github-pages/

    • Support for robots.txt: A robots file is now served by the Handler when /web/robots.txt exists

    • Internal code refactored to be more maintainable

    • Serving static resources can now be customized by implementing the ResourceProvider interface

    How to migrate from v6 to v7

    go-app v7 mainly introduced internal improvements. Despite trying to keep the API the same as v6, those changes resulted in API minor modifications that break compatibility.

    Here is a guide on how to adapt v6 code to make it work with v7.


    Go import instructions using v6:

    import (

    must be changed to v7:

    import (


    • RootDir field has been removed. Handler now uses the Resources field to define where app resources and static resources are located. This has a default value that is retro compatible with local static resources. If static resources are located on a remote bucket, use the following:

          Resources: app.RemoteBucket("BUCKET_URL"),
    • UseMinimalDefaultStyles field has been removed. go-app now use CSS styles that only apply to the loading screen and context menus. The former default styles have been removed since they could conflict with some CSS frameworks.

    Component interfaces

    Some interfaces to deals with the lifecycle of components have been modified to take a context as the first argument. Component with methods that satisfies the following interfaces must be updated:

    • Mounter: OnMount() become OnMount(ctx app.Context)
    • Navigator: OnNav(u *url.URL) become OnNav(ctx app.Context u *url.URL)

    Event handlers

    EventHandler function signature has been also modified to take a context as the first argument:

    • func(src app.Value, e app.Event) become func(ctx app.Context, e app.Event)

    • Source is now accessed from the context:

      // Event handler that retrieve input value when onchange is fired:
      func (c *myCompo) OnChange(ctx app.Context, e app.Event) {
          v := ctx.JSSrc().Get("value")
    Source code(tar.gz)
    Source code(zip)
Maxence Charriere
Maxence Charriere
Dom - A Go API for different Web APIs for WebAssembly target

Go DOM binding (and more) for WebAssembly This library provides a Go API for dif

Denys Smirnov 472 Jan 7, 2023
Golang-WASM provides a simple idiomatic, and comprehensive API and bindings for working with WebAssembly for Go and JavaScript developers

A bridge and bindings for JS DOM API with Go WebAssembly. Written by Team Ortix - Hamza Ali and Chan Wen Xu. GOOS=js GOARCH=wasm go get -u github.com/

TeamOrtix 93 Dec 22, 2022
Go compiler for small places. Microcontrollers, WebAssembly, and command-line tools. Based on LLVM.

TinyGo - Go compiler for small places TinyGo is a Go compiler intended for use in small places such as microcontrollers, WebAssembly (Wasm), and comma

TinyGo 12.1k Dec 30, 2022
WebAssembly interop between Go and JS values.

vert Package vert provides WebAssembly interop between Go and JS values. Install GOOS=js GOARCH=wasm go get github.com/norunners/vert Examples Hello W

null 83 Dec 28, 2022
WebAssembly for Proxies (Golang host implementation)

WebAssembly for Proxies (GoLang host implementation) The GoLang implementation for proxy-wasm, enabling developer to run proxy-wasm extensions in Go.

MOSN 38 Dec 29, 2022
🐹🕸️ WebAssembly runtime for Go

Wasmer Go Website • Docs • Slack Channel A complete and mature WebAssembly runtime for Go based on Wasmer. Features Easy to use: The wasmer API mimics

Wasmer 2.3k Jan 2, 2023
🐹🕸️ WebAssembly runtime for Go

Wasmer Go Website • Docs • Slack Channel A complete and mature WebAssembly runtime for Go based on Wasmer. Features Easy to use: The wasmer API mimics

Wasmer 2.3k Dec 29, 2022
Vugu: A modern UI library for Go+WebAssembly (experimental)

Vugu: A modern UI library for Go+WebAssembly (experimental)

Vugu 4.5k Jan 3, 2023
WebAssembly runtime for wasmer-go

gowasmer When compiling Go to WebAssembly, the Go compiler assumes the WebAssembly is going to run in a JavaScript environment. Hence a wasm_exec.js f

mattn 99 Dec 28, 2022
A template project to demonstrate how to run WebAssembly functions as sidecar microservices in dapr

Live Demo 1. Introduction DAPR is a portable, event-driven runtime that makes it easy for any developer to build resilient, stateless and stateful app

Second State 185 Jan 3, 2023
Tiny, blazing fast WebAssembly compute

Sat, the tiny WebAssembly compute module Sat (as in satellite) is an experiment, and isn't ready for production use. Please try it out and give feedba

Suborbital 320 Jan 5, 2023
WebAssembly Lightweight Javascript Framework in Go (AngularJS Inspired)

Tango Lightweight WASM HTML / Javascript Framework Intro WebAssembly is nice, Go on the web is nice, so I ported Tangu to Go and WebAssembly. Tangu is

enimatek 8 Dec 20, 2022
Running a Command line tool written in Go on browser with WebAssembly

Running a command line tool written in Go on browser with WebAssembly This repo contains code/assets from the article Files: . ├── article.md

wcchoi 82 Dec 30, 2022
This library provides WebAssembly capability for goja Javascript engine

This module provides WebAssembly functions into goja javascript engine.

YC-L 1 Jan 10, 2022
A Brainfuck to WebAssembly compiler written in Go.

brainfuck2wasm A Brainfuck to WebAssembly compiler written in Go. I am writing this compiler for a Medium article. When I complete the compiler, I'll

Luke I. Wilson 2 Jun 6, 2022
wazero: the zero dependency WebAssembly runtime for Go developers

wazero: the zero dependency WebAssembly runtime for Go developers WebAssembly is a way to safely run code compiled in other languages. Runtimes execut

Tetrate Labs 2.3k Jan 2, 2023
Aes for go and java; build go fo wasm and use wasm parse java response.

aes_go_wasm_java aes for go and java; build go fo wasm and use wasm parse java response. vscode setting config settings.json { "go.toolsEnvVars":

忆年 0 Dec 14, 2021
Bed and Breakfast web app written in Go

BOOKINGS AND RESERVATIONS This repository contains the files for my RareBnB application RareBnB is an "AirBnB" style clone providing a user the abilit

null 0 Jan 11, 2022
Thanks to Webassybly technology, we can develop front-end in Go+ language

gfront Thanks to Webassybly technology, we can develop front-end in Go+ language. Inspired of React, go-app and Go+ classfile Hello, world JS(React) i

Rangding Zhang 0 Feb 2, 2022