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 | Chart width height | Number|String | 720 | Chart height 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! :)