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rootJS

Node.js bindings for ROOT 6

Docs

Check this https://jenkins-rootjs.web.cern.ch/job/RootJS/doxygen/ for the current documentation. Documentation is generated by Jenkins, so this link should always point to a recent version.

Installation

rootJS is in the main npm package repository - all you have to do is have ROOT6 installed, then run npm install rootjs.

Testing

Simply run npm test after installing rootJS in development mode.

We currently use a mocha testsuite but might add something to (unit-)test C++ code directly.

Dependencies

• This module only supports Node.js v4.4 or newer
• You need to have ROOT-6.06.00 or newer installed (root-config needs to be available in your PATH)
• You need libuv, on Ubuntu you can use sudo apt-get install libuv1-dev to install it

Usage

You can use rootJS in a node shell by using require on the module directory, e.g.:

var root = require('rootjs');

Afterwards you have access to root's functionality through the required root object which copies its structure from ROOT.

> root.gProgName //You can access globals
'node'
> root.Compress("compress this text") //You can call global functions
'compressthistext'
> var browser = new root.TBrowser() //You can create new objects (even GUI elements)
undefined
> browser.SetName("test") //And run its methods
'165781144'
> browser.GetName()
'test'

Load libraries

You can easily load other ROOT libraries whenever needed, just use loadLibrary:

>root.loadlibrary("libMathCore.so") //Loads math core
0
>root.ROOT.Math.Pi()
3.141592653589793 //Verified!

Calling ROOT's gSystem.load("libName.so")to load a library is highly discouraged and may result in unexpected behaviour.

If neccessary a refresh of the exported functions can be done through refreshExports

>root.refreshExports() //Checks for additions to the gClassTable and exposes them
undefined

Callbacks

We support async code execution on every method call, just add a callback:

> root.gSystem.Exec("sleep 1", function() {
    console.log("this is called in the callback")
});
>console.log("Async called");
Async called // The second log is shown first because the other one will be called after "sleep 1"
undefined
> this is called in the callback

This will be usefull when processing huge amounts of data while setting up other parts of the environment.

Operators

C++ operators like "==" are supported, these operators are mapped on objects or in the global root object

> var t1 = new root.TString("test")
undefined
> var t2 = new root.TString("test")
undefined
> t1 == t2
false
> root._equals(t1, t2) // C++ == operator
true
 
> t1._at(1) //C++ []-operator
'e'
 
t1._call(2, 2).Data() //C++ ()-operator
'st'
 
t1._setAdd(" test2") //C++ += operator
undefined
> t1.Data()
'test test2'
 
//All implemented operators are prefixed with "_"