React Linechart

Highly customizable line charts using React! Check the Live Demo and follow along the tutorial.

1. Why
2. Installation
3. Usage
4. Properties Table
5. Tooltips
6. Derived Charts
7. Parsers
8. isDate
9. Improvements

Why

I always felt frustrated with the libraries out there which aim to implement this simple visualization. Many would lack basic features (such as adding multi lines or changing line colors) or would be extremely low-level (think d3). Built on top of d3, react-linechart provides necessary customization without losing simplicity.

Installation

npm install react-linechart --save

Usage

Add Line Charts with minimum configuration:

import React, { Component } from 'react';
import LineChart from 'react-linechart';
import '../node_modules/react-linechart/dist/styles.css';

export default class App extends Component {
	render() {
		const data = [
			{									
				color: "steelblue", 
				points: [{x: 1, y: 2}, {x: 3, y: 5}, {x: 7, y: -3}] 
			}
		];
		return (
			<div>
				<div className="App">
					<h1>My First LineChart</h1>
					<LineChart 
						width={600}
						height={400}
						data={data}
					/>
				</div>				
			</div>
		);
	}
}

This component is an attempt to simplify the rendering of a basic Line Chart by exposing many props that are commonly used. I realize it is very hard to encompass every use case, so I put an effort in making this especially pleasant to work with continuous values of numbers and dates.

The only mandatory prop is data - an array of objects describing the lines that will be rendered on screen. The typical line object follows this structure:

{
	id,
	name,
	color,
	points: [ { x, y } ]
}

Where id is an identificator for the line, name is a name for the line, color is a color for the line and points are an array of { x, y } objects representing the data. It would be particularly annoying if we need to parse our data to this format, so I provided a handful of parser functions that hopefully will meet most data formats commonly out there.

Properties Table

Property	Type	Default	Description
id	String	none	Unique ID for the visualization
data	Array<Object>	none	Data that describes lines to be rendered (required)
width	`Number	String`	1024
height	`Number	String`	720
margins	Object	{ top: 50, right: 20, bottom: 50, left: 55 }	Chart margins
xLabel	String	"X"	Label for the X axis
yLabel	String	"Y"	Label for the Y axis
hideXLabel	Bool	false	States if the X label is hidden
hideYLabel	Bool	false	States if the Y label is hidden
hideXAxis	Bool	false	States if the X axis is hidden
hideYAxis	Bool	false	States if the Y axis is hidden
xMin	String	none	Lower domain for the X axis
xMax	String	none	Higher domain for the X axis
yMin	String	none	Lower domain for the Y axis
yMax	String	none	Higher domain for the Y axis
isDate	Bool	false	Determines if we need to treat the X dimension as date (or numeric)
xParser	Function	isDate ? d3.time.format("%Y-%m-%d").parse : ((x) => x)	Parse X values before scaling
xDisplay	Function	isDate ? d3.time.format("%b %d") : d3.format("d")	Parse X values before displaying
ticks	Number	10	Chart width.
hideLines	Bool	false	States if lines are drawn
interpolate	String	"cardinal"	Line interpolation function
hidePoints	Bool	false	States if points are shown
pointRadius	Number	5	Point radius in pixels
onPointClick	Function	(event, point) => console.log(point)	Callback for clicking on points
onPointHover	Function	none	Callback for hovering on points
onTextClick	Function	(text) => console.log(text)	Callback for clicking on texts
onTextHover	Function	none	Callback for hovering on texts
showLegends	Bool	false	States if legends are shown
legendPosition	String	"top-left"	Position where the legend is rendered
tooltipClass	String	"svg-line-chart-tooltip"	Tooltip class
pointClass	String	"svg-line-chart-point"	Point class
labelClass	String	"svg-line-chart-label"	Label class

Tooltips

It is easy to hook tooltips onto your chart. Just provide a function on the onPointHover prop that returns a HTML element and this will be displayed inside the tooltip. You can use the class provided by default or write your own and pass to the chart as a tooltipClass prop.

Derived Charts

Turns out a simple Line Chart with the right props can assume a different aspect. For example, setting hideLines={true} gives an awesome Scatter Plot.

import { ScatterPlot } from 'react-linechart'
...
render() {
	return <ScatterPlot id="my-scatter-plot" data={data} />
}

It is also possible to build a "Stair Chart", which is how I am calling a time-table-ish kind of chart when we have start and end dates and want to display them as nice stacked bars. Check the Live Demo to get a better insight.

import { StairChart } from 'react-linechart'
...
render() {
	return <StairChart id="my-stair-chart" data={stairedData} />
}

You can add optional onTextHover and onTextClick functions to interact with the chart.

Parsers

In order to comply with the format specified, you can use 3 utilitaries functions which parse your raw data. They are the following:

parseFlatArray(data, xDimension, yDimensionArray, colorArray, idArray, nameArray)

Parameter	Type	Default	Description
data	Array<Objects>	none	Array of objects describing your data in a flat format
xDimensions	String	none	Property that will serve as X dimension
yDimensionArray	Array<Strings>	none	Array of properties that will serve as Y dimension
colorArray	Array<Strings>	[]	Array of hex strings colors that will be assigned in accordance with the yDimensionArray. If no colors are specified, a default array of 20 colors is used
idArray	Array<Strings>	[]	Array of ids that will be assigned in accordance with yDimensionArray. If no ids are specified, a combination of X and Y dimensions is used
nameArray	Array<Strings>	[]	Array of names that will be assigned in accordance with yDimensionArray

This is useful when you want to display a multi-line chart in a one-data-per-object basis. Just pick the dimensions you want and the chart will be rendered.

const gsmData = [
	{
		"Year": 1880,
		"Glob": -19,
		"NHem": -33,
		"SHem": -5,		
	},
	{
		"Year": 1881,
		"Glob": -10,
		"NHem": -18,
		"SHem": -2,
	},
	...
];

// Creates a three-line chart: Glob x Year, Glob x NHem, Glob x SHem
const gsmFlat = parseFlatArray(gsmData, "Year", ["Glob", "NHem", "SHem"]);

parseGroupingBy(data, xDimension, yDimension, groupByDimension, nameGenerator, colorArray, idArray)

Parameter	Type	Default	Description
data	Array<Objects>	none	Array of objects describing your data in an indexed format
xDimensions	String	none	Property that will serve as X dimension
yDimension	String	none	Property that will serve as Y dimension
groupByDimension	String	none	Dimension that will be group lines together
nameGenerator	Function	nameGenerator : (i) => `Grouped by ${groupByDimension} = ${i}`;	Function that will generate a name based on the groupByDimension value
colorArray	Array<Strings>	[]	Array of hex strings colors that will be assigned in accordance with the yDimensionArray. If no colors are specified, a default array of 20 colors is used
idArray	Array<Strings>	[]	Array of ids that will be assigned in accordance with yDimensionArray. If no ids are specified, a combination of X and Y dimensions is used

This is useful when you want to aggregate data based on some dimension, an id, for example.

const data = [
	{ id: 1, value: 3, date: "2016-01-01" },
	{ id: 1, value: 4, date: "2016-01-03" },
	{ id: 2, value: 10, date: "2016-01-02" },
	{ id: 1, value: 6, date: "2016-01-04" },
	{ id: 2, value: 13, date: "2016-01-06" },
	{ id: 1, value: 5, date: "2016-01-08" },
	{ id: 2, value: 10, date: "2016-03-20" }
];

const grouped = parseGroupingBy(data, "date", "value", "id");

parseStairChart(data, start, end, name, color)

Parameter	Type	Default	Description
data	Array<Objects>	none	Array of objects describing your data
start	String	none	Property that will serve as start date
end	String	none	Property that will serve as end date
name	String	none	Property that will serve as name for the given line
color	String	"steelblue"	Color to fill the line

This is useful when you want to display a kind of time frame.

const stair = [
	{ startDate: "2016-01-01", endDate: "2016-01-04", name: "Task 1" },
	{ startDate: "2016-01-02", endDate: "2016-01-03", name: "Task 2" },
	{ startDate: "2016-01-03", endDate: "2016-01-06", name: "Task 3" },
	{ startDate: "2016-01-05", endDate: "2016-01-10", name: "Task 4" },
	{ startDate: "2016-01-08", endDate: "2016-01-13", name: "Task 5" },
	{ startDate: "2016-01-09", endDate: "2016-01-20", name: "Task 6" }
];
const staired = parseStairChart(stair, "startDate", "endDate", "name");

isDate

The component has a shortcut isDate property which will try to parse your x input as a Date. If you use a numeric value and pass isDate={true}, then unexpected behaviour will happen (same for the reverse). This is supposed to be helpful considering standard scenarios but you can always use the xParser prop to parse whatever data you have to a numeric value and the xDisplay prop to display whatever numeric value you have to something more meaningful to your visualization.

Meanwhile, by default the component will first parse the date in a "YYYY-MM-DD" format in a Date object. By default I'm using d3 functions, but you can write your own or use another Date parser such as MomentJS.

Improvements

This is a work in progress, so expect things to break. You can fork your own version or, better still, contribute for the completeness of this library. Help me making a great tool! :)