kapouer / v8

Embedded JavaScript Engine for R

V8

Embedded JavaScript and WebAssembly Engine for R

An R interface to V8: Google's open source JavaScript and WebAssembly engine. This package can be compiled either with V8 version 6 and up or NodeJS when built as a shared library.

Getting started

About the R package:

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

To see some quick examples in R run:

library(V8)
example(v8)

Installation

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

install.packages("V8")

On Linux you need a suitable libv8 installation, see below.

Linux: Static libv8

On amd64/arm64 Linux/MacOS platforms it is possible (and recommended) to automatically download a suitable static build of libv8 during package installation. This is enabled by default on Ubuntu, RHEL, and MacOS. For other systems you can opt-in by setting an environment variable DOWNLOAD_STATIC_LIBV8 during installation, for example:

Sys.setenv(DOWNLOAD_STATIC_LIBV8 = 1)
install.packages("V8")

This way, you can install the R package on any x64 Linux system, without external system requirements. Alternatively, it is also still possible to install libv8 from your distribution as described below. This may be needed for servers running other architectures, or when building the R package without internet access.

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

Fedora / Redhat

On Fedora we need v8-devel (which Fedora provides as part of nodejs):

sudo yum install v8-devel

On CentOS 7 / RHEL 7 we install first need to enable EPEL:

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

On CentOS 8 / RHEL 8, v8-devel can be installed from the nodejs:16-epel module repository:

sudo yum --refresh install @nodejs:16-epel/minimal v8-devel 

Arch Linux

Arch users are advised to install the v8-r package, which has been configured to work well with R. Installation can done through your preferred AUR helper such as yay, Trizen, etc. However, since V8 contains a large codebase and (re-)compilation takes a while, users may prefer to build and update it manually. For example,

## Arch
cd /tmp
yay -G v8-r   
cd v8-r
makepkg -si

Homebrew

On OS-X use v8 from Homebrew:

brew install v8

But it is much easier to set DOWNLOAD_STATIC_LIBV8 instead.

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)