jupyter_contrib_nbextensions/nbextensions/usability/splitcell/splitcell.js

// Allow for split cells in jupyter notebooks

define([
	'base/js/namespace',
    'services/config',
    'base/js/utils'
    ], function(Jupyter, configmod, utils){
	"use strict";

	//create config object to load paramters
	var base_url = utils.get_body_data("baseUrl");
	var config = new configmod.ConfigSection('notebook', {base_url: base_url});

	//define default config parameter values
	var params = {
		toggle_cell_style_keybinding : 'shift-s'
	};

	//updates default params with any specified in the server's config
	var update_params = function(){
		for (var key in params){
			if (config.data.hasOwnProperty(key)){
				params[key] = config.data[key];
			}
		}
	};

	config.loaded.then(function(){
		// update defaults
		update_params();

		//register actions with ActionHandler instance
		var prefix = 'auto';
		var name = 'toggle-cell-style';
		var action = {
			icon : 'fa-arrows-h',
			help : 'Toggle split/centered cell style',
			help_index : 'eb',
			id : 'split_cells',
			handler : toggle_cell_style
					};

		var action_full_name = Jupyter.keyboard_manager.actions.register(action, name, prefix);

		//define keyboard shortucts
		var command_mode_shortcuts = {};
		command_mode_shortcuts[params.toggle_cell_style_keybinding] =  action_full_name;

		//register keyboard shortucts with keyboard_manager
		Jupyter.notebook.keyboard_manager.command_shortcuts.add_shortcuts(command_mode_shortcuts);
		Jupyter.toolbar.add_buttons_group([action_full_name]);
	});


	var toggle_cell_style = function(){
		var cell = Jupyter.notebook.get_selected_cell();
		if (!("cell_style" in cell.metadata)){cell.metadata.cell_style = 'split';}
		else if (cell.metadata.cell_style == 'center'){cell.metadata.cell_style = 'split';}
		else {cell.metadata.cell_style = 'center';}

		update_cell_style_element(cell);
	}

	var get_cell_style_html = function(cell_style){
		console.log(cell_style)
        if (cell_style == "split") 
            {return "float:left; width:50%;";}
        return "width:100%;";
    	};

    var update_cell_style_element = function(cell){
    	var cell_style_html = get_cell_style_html(cell.metadata.cell_style);
    	cell.element.attr('style', cell_style_html);
    	}

    // On Load lets set the cell styles correctly
	var cells = Jupyter.notebook.get_cells();
	var ncells = Jupyter.notebook.ncells();

    for (var i=0; i<ncells; i++){
    	var cell = cells[i];
    	if ("cell_style" in cell.metadata){
    		update_cell_style_element(cell, cell.metadata.cell_style)
    	};
   	 };


	var load_extension = function() {
		config.load();

		};

	return {
		load_ipython_extension : load_extension
		};
});