GopherJS:从 Go 到 JavaScript 的编译器，用于在浏览器中运行 Go 代码-开源

GopherJS - A compiler from Go to JavaScript ------------------------------------------- [](https://godoc.org/github.com/gopherjs/gopherjs/js) [](https://sourcegraph.com/github.com/gopherjs/gopherjs?badge) [](https://circleci.com/gh/gopherjs/gopherjs) GopherJS compiles Go code ([golang.org](https://golang.org/)) to pure JavaScript code. Its main purpose is to give you the opportunity to write front-end code in Go which will still run in all browsers. ### What's new? - 2021-04-04: **Go 1.16 is now officially supported!** 🎉 🎉 🎉 ### Playground Give GopherJS a try on the [GopherJS Playground](http://gopherjs.github.io/playground/). ### What is supported? Nearly everything, including Goroutines ([compatibility documentation](https://github.com/gopherjs/gopherjs/blob/master/doc/compatibility.md)). Performance is quite good in most cases, see [HTML5 game engine benchmark](https://ajhager.github.io/engi/demos/botmark.html). Cgo is not supported. ### Installation and Usage GopherJS [requires Go 1.16 or newer](https://github.com/gopherjs/gopherjs/blob/master/doc/compatibility.md#go-version-compatibility). If you need an older Go version, you can use an [older Gopher release](https://github.com/gopherjs/gopherjs/releases). Get or update GopherJS and dependencies with: ``` go get -u github.com/gopherjs/gopherjs ``` If your local Go distribution as reported by `go version` is newer than Go 1.16, then you need to set the `GOPHERJS_GOROOT` environment variable to a directory that contains a Go 1.16 distribution. For example: ``` go get golang.org/dl/go1.16.3 go1.16.3 download export GOPHERJS_GOROOT="$(go1.16.3 env GOROOT)" # Also add this line to your .profile or equivalent. ``` Now you can use `gopherjs build [package]`, `gopherjs build [files]` or `gopherjs install [package]` which behave similar to the `go` tool. For `main` packages, these commands create a `.js` file and `.js.map` source map in the current directory or in `$GOPATH/bin`. The generated JavaScript file can be used as usual in a website. Use `gopherjs help [command]` to get a list of possible command line flags, e.g. for minification and automatically watching for changes. `gopherjs` uses your platform's default `GOOS` value when generating code. Supported `GOOS` values are: `linux`, `darwin`. If you're on a different platform (e.g., Windows or FreeBSD), you'll need to set the `GOOS` environment variable to a supported value. For example, `GOOS=linux gopherjs build [package]`. *Note: GopherJS will try to write compiled object files of the core packages to your $GOROOT/pkg directory. If that fails, it will fall back to $GOPATH/pkg.* #### gopherjs run, gopherjs test If you want to use `gopherjs run` or `gopherjs test` to run the generated code locally, install Node.js 10.0.0 (or newer), and the `source-map-support` module: ``` npm install --global source-map-support ``` On supported `GOOS` platforms, it's possible to make system calls (file system access, etc.) available. See [doc/syscalls.md](https://github.com/gopherjs/gopherjs/blob/master/doc/syscalls.md) for instructions on how to do so. #### gopherjs serve `gopherjs serve` is a useful command you can use during development. It will start an HTTP server serving on ":8080" by default, then dynamically compile your Go packages with GopherJS and serve them. For example, navigating to `http://localhost:8080/example.com/user/project/` should compile and run the Go package `example.com/user/project`. The generated JavaScript output will be served at `http://localhost:8080/example.com/user/project/project.js` (the .js file name will be equal to the base directory name). If the directory contains `index.html` it will be served, otherwise a minimal `index.html` that includes `<script src="project.js"></script>` will be provided, causing the JavaScript to be executed. All other static files will be served too. Refreshing in the browser will rebuild the served files if needed. Compilation errors will be displayed in terminal, and in browser console. Additionally, it will serve $GOROOT and $GOPATH for sourcemaps. If you include an argument, it will be the root from which everything is served. For example, if you run `gopherjs serve github.com/user/project` then the generated JavaScript for the package github.com/user/project/mypkg will be served at http://localhost:8080/mypkg/mypkg.js. #### Environment Variables There is one GopherJS-specific environment variable: - `GOPHERJS_GOROOT` - if set, GopherJS uses this value as the default GOROOT value, instead of using the system GOROOT as the default GOROOT value - `GOPHERJS_SKIP_VERSION_CHECK` - if set to true, GopherJS will not check Go version in the GOROOT for compatibility with the GopherJS release. This is primarily useful for testing GopherJS against unreleased versions of Go. ### Performance Tips - Use the `-m` command line flag to generate minified code. - Apply gzip compression (https://en.wikipedia.org/wiki/HTTP_compression). - Use `int` instead of `(u)int8/16/32/64`. - Use `float64` instead of `float32`. ### Community - [#gopherjs Channel on Gophers Slack](https://gophers.slack.com/messages/gopherjs/) (invites to Gophers Slack are available [here](http://blog.gopheracademy.com/gophers-slack-community/#how-can-i-be-invited-to-join:2facdc921b2310f18cb851c36fa92369)) - [Bindings to JavaScript APIs and libraries](https://github.com/gopherjs/gopherjs/wiki/bindings) - [GopherJS Blog](https://medium.com/gopherjs) - [GopherJS on Twitter](https://twitter.com/GopherJS) ### Getting started #### Interacting with the DOM The package `github.com/gopherjs/gopherjs/js` (see [documentation](https://godoc.org/github.com/gopherjs/gopherjs/js)) provides functions for interacting with native JavaScript APIs. For example the line ```js document.write("Hello world!"); ``` would look like this in Go: ```go js.Global.Get("document").Call("write", "Hello world!") ``` You may also want use the [DOM bindings](http://dominik.honnef.co/go/js/dom), the [jQuery bindings](https://github.com/gopherjs/jquery) (see [TodoMVC Example](https://github.com/gopherjs/todomvc)) or the [AngularJS bindings](https://github.com/wvell/go-angularjs). Those are some of the [bindings to JavaScript APIs and libraries](https://github.com/gopherjs/gopherjs/wiki/bindings) by community members. #### Providing library functions for use in other JavaScript code Set a global variable to a map that contains the functions: ```go package main import "github.com/gopherjs/gopherjs/js" func main() { js.Global.Set("pet", map[string]interface{}{ "New": New, }) } type Pet struct { name string } func New(name string) *js.Object { return js.MakeWrapper(&Pet{name}) } func (p *Pet) Name() string { return p.name } func (p *Pet) SetName(name string) { p.name = name } ``` For more details see [Jason Stone's blog post](http://legacytotheedge.blogspot.de/2014/03/gopherjs-go-to-javascript-transpiler.html) about GopherJS. ### Architecture #### General GopherJS emulates a 32-bit environment. This means that `int`, `uint` and `uintptr` have a precision of 32 bits. However, the explicit 64-bit integer types `int64` and `uint64` are supported. The `GOARCH` value of GopherJS is "js". You may use it as a build constraint: `// +build js,-wasm`. #### Application Lifecycle The `main` function is executed as usual after all `init` functions have run. JavaScript callbacks can also invoke Go functions, even after the `main` function has exited. Therefore the end of the `main` function should not be regarded as the end of the application and does not end the execution of other goroutines. In the browser, calling `os.Exit` (e.g. indirectly by `log.Fatal`) also does not terminate the execution of th