Skip to content
Execute JavaScript from Go
Go C++ C Python
Branch: master
Clone or download
rogchap use go1.13 to run tests (#1)
* use go1.13 to run tests

* Update ci to build against master

* env for modules is needed for Go 1.12
Latest commit 9b8bf35 Sep 15, 2019

README.md

Execute JavaScript from Go

Go Report Card GoDoc Build Status

V8 Gopher based on original artwork from the amazing Renee French

Usage

import "rogchap.com/v8go"

Running a script

ctx, _ := v8go.NewContext(nil) // creates a new V8 context with a new Isolate aka VM
ctx.RunScript("const add = (a, b) => a + b", "math.js") // executes a script on the global context
ctx.RunScript("const result = add(3, 4)", "main.js") // any functions previously added to the context can be called
val, _ := ctx.RunScript("result", "value.js") // return a value in JavaScript back to Go
fmt.Printf("addition result: %s", val)

One VM, many contexts

vm, _ := v8go.NewIsolate() // creates a new JavaScript VM
ctx1, _ := v8go.NewContext(vm) // new context within the VM
ctx1.RunScript("const multiply = (a, b) => a * b", "math.js")

ctx2, _ := v8go.NewContext(vm) // another context on the same VM
if _, err := ctx2.RunScript("multiply(3, 4)", "main.js"); err != nil {
  // this will error as multiply is not defined in this context
}

Javascript errors

val, err := ctx.RunScript(src, filename)
if err != nil {
  err = err.(v8go.JSError) // JavaScript errors will be returned as the JSError struct
  fmt.Println(err.Message) // the message of the exception thrown
  fmt.Println(err.Location) // the filename, line number and the column where the error occured
  fmt.Println(err.StackTrace) // the full stack trace of the error, if available

  fmt.Printf("javascript error: %v", err) // will format the standard error message
  fmt.Printf("javascript stack trace: %+v", err) // will format the full error stack trace
}

Terminate long running scripts

vals := make(chan *v8go.Value, 1)
errs := make(chan error, 1)

go func() {
    val, err := ctx.RunScript(script, "forever.js") // exec a long running script
    if err != nil {
        errs <- err
        return
    }
    vals <- val
}()

select {
case val := <- vals:
    // sucess
case err := <- errs:
    // javascript error
case <- time.After(200 * time.Milliseconds):
    vm, _ := ctx.Isolate() // get the Isolate from the context
    vm.TerminateExecution() // terminate the execution 
    err := <- errs // will get a termination error back from the running script
}

Documentation

GoDoc: https://godoc.org/rogchap.com/v8go

V8 dependency

V8 version: 7.6.303.31

In order to make v8go usable as a standard Go package, prebuilt static libraries of V8 are included for Linux and OSX ie. you should not require to build V8 yourself.

V8 requires 64-bit, therefore will not work on 32-bit systems.


V8 Gopher image based on original artwork from the amazing Renee French.

You can’t perform that action at this time.