JavaScript::D3

Generation of JavaScript's D3 code for plots and charts.

JavaScript::D3 Raku package

This repository has the a Raku package for generation of JavaScript's D3 code for making plots and charts.

This package is intended to be used in Jupyter notebooks with the Raku kernel implemented by Brian Duggan, [BD1]. The commands of the package generate JavaScript code produce (nice) D3.js plots or charts.

For illustrative examples see the Jupyter notebook "Tests-for-JavaScript-D3".

The (original versions of the) JavaScript snippets used in this package are taken from "The D3.js Graph Gallery".

Mission statement

Make first class -- beautiful, tunable, and useful -- plots and charts with Raku using concise specifications.

Design and philosophy

Here is a list of guiding design principles:

Concise plot and charts specifications.
Using Mathematica's plot functions for commands signatures inspiration. (Instead of, say, R's "ggplot2".)
- For example, see ListPlot, BubbleChart.
The primary target data structure to visualize is an array of hashes, with all array elements having the one of these sets of keys
- <x y>
- <x y group>
- <x y z>
- <x y z group>
Multiple-dataset plots are produced via dataset records that have the key "group".
Whenever possible deduce the keys from arrays of scalars.
The data reshaping functions in "Data::Reshapers", [AAp1], should fit nicely into workflows with this package.
The package functions are tested separately:
- As Raku functions that produce output for given signatures
- As JavaScript plots that correspond to the corresponding intents

How does it work?

Here is a diagram that summarizes the evaluation path from a Raku plot spec to a browser diagram:

Here is the corresponding narration:

Enter Raku plot command in cell that starts with the magic spec %% js.
- Like js-d3-list-plot((^12)>>.rand).
Jupyter via the Raku kernel evaluates the Raku plot command.
The Raku plot command produces JavaScript code.
The Jupyter "lets" the web browser to evaluate the obtained JavaScript code.
- Instead of web browser, say, Visual Studio Code can be used.

The evaluation loop spelled out above is possible because of the magics implementation in the Raku package Jupyter::Kernel, [BD1].

Alternatives

Raku packages

The Raku packages "Text::Plot", [AAp2], and "SVG::Plot", [MLp1], provide similar functionalities and both can be used in Jupyter notebooks. (Well, "Text::Plot" can be used anywhere.)

Different backend

Instead of using D3.js as a "backend" it is possible -- and instructive -- to implement Raku plotting functions that generate JavaScript code for the library Chart.js.

D3.js is lower level than Chart.js, hence in principle Chart.js is closer to the mission of this Raku package. I.e. at first I considered having Raku plotting implementations with Chart.js (in a package called "JavaScript::Chart".) But I had hard time making Chart.js plots work consistently within Jupyter.

Command Line Interface (CLI)

The package provides a CLI script that can be used to generate HTML files with plots or charts.

js-d3-graphics --help

# Usage:
#   js-d3-graphics <cmd> [<points> ...] [-p|--point-char=<Str>] [-w|--width[=UInt]] [-h|--height[=UInt]] [-t|--title=<Str>] [--x-label=<Str>] [--y-label=<Str>] [--background=<Str>] [--color=<Str>] [--format=<Str>] -- Makes textual (terminal) plots.
#   js-d3-graphics <cmd> <words> [-w|--width[=UInt]] [-h|--height[=UInt]] [-t|--title=<Str>] [--x-label=<Str>] [--y-label=<Str>] [--background=<Str>] [--color=<Str>] [--format=<Str>] -- Makes textual (terminal) plots by splitting a string of data points.
#   js-d3-graphics <cmd> [-w|--width[=UInt]] [-h|--height[=UInt]] [-t|--title=<Str>] [--x-label=<Str>] [--y-label=<Str>] [--background=<Str>] [--color=<Str>] [--format=<Str>] -- Makes textual (terminal) plots from pipeline input
#
#     <cmd>                    Graphics command.
#     [<points> ...]           Data points.
#     -p|--point-char=<Str>    Plot points character. [default: '*']
#     -w|--width[=UInt]        Width of the plot. (-1 for Whatever.) [default: 800]
#     -h|--height[=UInt]       Height of the plot. (-1 for Whatever.) [default: 600]
#     -t|--title=<Str>         Title of the plot. [default: '']
#     --x-label=<Str>          Label of the X-axis. If Whatever, then no label is placed. [default: '']
#     --y-label=<Str>          Label of the Y-axis. If Whatever, then no label is placed. [default: '']
#     --background=<Str>       Image background color [default: 'white']
#     --color=<Str>            Color. [default: 'steelblue']
#     --format=<Str>           Output format, one of 'jupyter' or 'html'. [default: 'html']
#     <words>                  String with data points.

Here is an usage example that produces a list line plot:

 js-d3-graphics list-line-plot 1 2 2 12 33 41 15 5 -t="Nice plot" --x-label="My X" --y-label="My Y" > out.html && open out.html

Here is an example that produces bubble chart:

js-d3-graphics bubble-chart "1,1,10 2,2,12 33,41,15 5,3,30" -t="Nice plot" --x-label="My X" --y-label="My Y" > out.html && open out.htm

TODO

In the lists below the highest priority items are placed first.

Plots

Single dataset

DONE List plot
DONE List line plot
DONE Date list plot
TODO Box plot

Multiple dataset

TODO List plot
TODO List line plot
DONE Date list plot
TODO Box plot

Charts

Single dataset

DONE Bar chart
DONE Histogram
DONE Bubble chart
TODO Density 2D chart -- rectangular bins
TODO Radar chart
TODO Density 2D chart -- hexagonal bins
TODO Pie chart

Multiple dataset

TODO Bar chart
TODO Histogram
DONE Bubble chart
DONE Bubble chart with tooltips
TODO Pie chart
TODO Radar chart

Decorations

User specified or automatic:

DONE Plot label / title
DONE Axes labels
DONE Plot margins
DONE Plot legends (automatic for multi-datasets plots and chart)
TODO Title style (font size, color, face)
TODO Axes labels style (font size, color, face)

Infrastructural

DONE Support for different JavaScript wrapper styles
- DONE Jupyter cell execution ready
- DONE Standard HTML
- Result output with JSON format?
TODO Better, comprehensive type checking
- Using the type system of "Data::Reshapers", [AAp1], would be ideal, but I do not want to introduce such a "heavy" dependency.
DONE CLI script
TODO JavaScript code snippets management
- If they become too many.

Implementation details

Splicing of JavaScript snippets

The package works by splicing of parametrized JavaScript code snippets and replacing the parameters with concrete values.

In a sense, JavaScript macros are used to construct the final code through text manipulation. (Probably, unsound software-engineering-wise, but it works.)