V8

Embedded JavaScript Engine for R

An R interface to Google’s open source JavaScript engine. This package can now be compiled either with V8 version 6+ (LTS) from nodejs or with the legacy 3.14/3.15 version of V8.

Documentation

About the R package:

• Vignette: Introduction to V8 for R
• Vignette: Using NPM packages in V8 with browserify

Installation

Binary packages for OS-X or Windows can be installed directly from CRAN:

install.packages("V8")

Debian / Ubuntu

Installation from source on Linux requires libv8. On Ubuntu / Debian you need to install either libv8-dev, or libnode-dev. On the latest systems, libv8-dev is actually an alias for libnode-dev so they are the same:

# Debian and Ubuntu
sudo apt-get install -y libv8-dev

Backports for Xenial and Bionic

Ubuntu versions before 19.04 ship with a rather old V8 engine in libv8-dev. The R package can be compiled against this, but the engine only supports ES5, so some “modern” JavaScript syntax may not work. A lot of JS libraries these days require this.

A recent version of the V8 engine is available in libnode-dev from our the cran/v8 PPA:

# Ubuntu Xenial (16.04) and Bionic (18.04) only
sudo add-apt-repository ppa:cran/v8
sudo apt-get update
sudo apt-get install libnode-dev

After installing libnode-dev you need to reinstall the R package, and you should be good to go.

Travis CI

The above PPA is enabled by default in Travis for R 3.5 and up. You can use the following configuration to check R packges that depend on V8:

dist: xenial
addons:
  apt:
    packages: libnode-dev

You should delete the travis repository package cache if you switch from libv8-dev to libnode-dev.

The .travis.yml in the V8 repository shows other possible configurations.

Fedora / Redhat

On Fedora we need v8-devel:

sudo yum install v8-devel

On CentOS / RHEL we install v8-devel via EPEL:

sudo yum install epel-release
sudo yum install v8-devel

Homebrew

On OS-X use v8 from Homebrew:

brew install v8

On other systems you might need to install libv8 from source.

Hello World

# Create a new context
library(V8)
ctx <- v8()

# Evaluate some code
ctx$eval("var foo = 123")
ctx$eval("var bar = 456")
ctx$eval("foo+bar")

# Assign / get objects
ctx$assign("foo", JS("function(x){return x*x}"))
ctx$assign("bar", JS("foo(9)"))
ctx$get("bar")

Call functions from JavaScript libraries

ctx <- V8::v8()
ctx$source("https://cdnjs.cloudflare.com/ajax/libs/coffee-script/1.4.0/coffee-script.min.js")
jscode <- ctx$call("CoffeeScript.compile", "square = (x) -> x * x", list(bare = TRUE))
ctx$eval(jscode)
ctx$call("square", 9)