JS extension.

Contrary to general IPython extensions, Jupyter notebook extensions are written in javascript (or css). They are used to change the behaviour, functionality or UI of the Jupyter notebook.

Most of the time you should install nbextensions in the directory of the same name, either system wide or in your user profile. Most nbextensions provide the documentation to indicate how they should be installed.

Activating nbextensions

This part describes how to decide which nbextensions are loaded. If you are an end-user, and not interested in developing your own nbextension, you can skip this section.

Nbextension can easily be loaded using their name, if

• they are installed in either the local or global nbextension folders
• their entry point is named <extensionname>.js
• the extension defines an AMD module definition that exposes the method load_ipython_extension

Here is a minimal example of an AMD extension.

define(function(){
  return {
    // this will be called at extension loading time
    //---
    load_ipython_extension: function(){
        console.log("I have been loaded ! -- my nb extension");
    }
    //---
  };
})

Without further action, the extension can be dynamically loaded inside of a Jupiter notebook:

%%javascript
IPython.load_extensions('custom_shortcuts');

To load the extension automatically on start up, the IPython configuration has to be modified. To see the current value of the config in a notebook, open a Jupiter notebook, and type the following in the javascript console of your browser:

IPython.notebook.config

The value should be something like ConfigSection {section_name: "notebook", base_url: "/", data: Object, …}. If no extensions are installed, the data attribute (IPython.notebook.config.data) should be empty.

By updating the config, we can register a new extension to be loaded on start up.

First, the new config value is created:

var new_data = {"load_extensions":{"my_ext":true}}

The value assigned to "my_ext" should be non-null. Setting the value to null would remove the key from the configuration object. However, to keep everthing clear and clean, true should be used.

To actually update the config file, the update function of the config object has to called:

IPython.notebook.config.update(new_data)

Or as a one-liner:

IPython.notebook.config.update({"load_extensions":{"my_ext":true}})

The config is technically stored as a json object in ~/.ipython/profile_default/nbconfig/notebook.json

For example in our case :

// notebook.json
{
  "load_extensions": {
    "my_ext": true
  }
}

You should not update this file manually as it can be used by extension authors to modify configuration programmatically. Extension authors can also provide more convenient methods to activate extensions.