npm package: @freecodecamp/react-calendar-heatmap
Description: A calendar heatmap component built on SVG, inspired by Github's commit calendar graph.
Author: Kevin Qi
Latest version: 1.1.0

# React Calendar Heatmap

A calendar heatmap component built on SVG, inspired by github's commit calendar graph. The component expands to size of container and is super configurable. [**Try it out on CodeSandbox**](https://codesandbox.io/s/73mk9wlyx).

[![npm version](https://badge.fury.io/js/react-calendar-heatmap.svg)](https://badge.fury.io/js/react-calendar-heatmap)
[![Build Status](https://travis-ci.org/kevinsqi/react-calendar-heatmap.svg?branch=master)](https://travis-ci.org/kevinsqi/react-calendar-heatmap)
[![bundle size](https://img.shields.io/bundlephobia/min/react-calendar-heatmap.svg)](https://bundlephobia.com/result?p=react-calendar-heatmap)

[![react-calendar-heatmap screenshot](/demo/public/react-calendar-heatmap.png?raw=true)](https://codesandbox.io/s/73mk9wlyx)

## Setup

Install the npm module with yarn or npm:

```bash
yarn add react-calendar-heatmap
```

## Usage

Import the component:

```javascript
import CalendarHeatmap from 'react-calendar-heatmap';
```

Import styles. You can directly import from the module, which requires a CSS loader:

```javascript
import 'react-calendar-heatmap/dist/styles.css';
```

A CSS loader is included by default in create-react-app. If you don't have a CSS loader, you can simply [copy the stylesheet](src/styles.css) into a file in your project and import it instead.

To show a basic heatmap from January 1st to April 1st:

```javascript
<CalendarHeatmap
  startDate={new Date('2016-01-01')}
  endDate={new Date('2016-04-01')}
  values={[
    { date: '2016-01-01', count: 12 },
    { date: '2016-01-22', count: 122 },
    { date: '2016-01-30', count: 38 },
    // ...and so on
  ]}
/>
```

## Props

| Name | Type | Description |
| ---- | ---- | ----------- |
| `values` | **Required**, Array of Object | Required array of objects which each have a date property, which can be a Date object, parseable string, or millisecond timestamp. Example: `[{ date: '2016-01-01', count: 6 }]` |
| `startDate` | String, Number, or Date | Start of date range. |
| `endDate` | String, Number, or Date | End of date range - a Date object, parseable string, or millisecond timestamp. |
| `showMonthLabels` | Boolean | Toggle for removing month labels. |
| `showWeekdayLabels` | Boolean | Toggle for removing weekday labels. |
| `showOutOfRangeDays` | Boolean | Toggle display of extra days in week that are past endDate and before beginning of range. |
| `horizontal` | Boolean | Whether to orient horizontally or vertically. Can be used in combination with numDays/endDate to show just the current month. |
| `gutterSize` | Number | Size of gutters relative to squares. |
| `onClick` | Function | Callback to invoke when a square is clicked, e.g. `(value) => alert(value)` |
| `onMouseOver` | Function | Callback to invoke when mouse pointer is over a square, e.g. `(event, value) => console.log(event, value)` |
| `onMouseLeave` | Function | Callback to invoke when mouse pointer leaves a square, e.g. `(event, value) => console.log(event, value)` |
| `titleForValue` | Function | Function to determine each square's title attribute, for generating 3rd party hover tooltips (may also need to configure tooltipDataAttrs). Example: `(value) => `Date is ${value.date}` |
| `tooltipDataAttrs` | Object or Function | Set data attributes for all squares, for generating 3rd party hover tooltips. Either an object like `{ 'data-tooltip': 'tooltip' }` or a function like `(value) => { return { 'data-tooltip': 'Tooltip: ' + value } }` |
| `classForValue` | Function | Callback for determining CSS class to apply to each value, e.g. `(value) => (value.count > 0 ? 'blue' : 'white')`. |
| `monthLabels` | Array of String | An array with 12 strings representing the text from January to December, e.g. `['01', '02', ..., '12']` |
| `weekdayLabels` | Array of String | An array with 7 strings representing the text from Sunday to Saturday |
| `transformDayElement` | Function | A function to further transform generated svg element for a single day. Can be used to attach event handlers, add tooltips and more. Example: `(element, value, index) => React.cloneElement(element, { title: value.date })`. |


## Configuring colors

To use the color scale shown in the [live demo](https://www.kevinqi.com/react-calendar-heatmap/) based on the github contribution graph, you can set the `classForValue` prop, a function that determines which CSS class to apply to each value:

```javascript
<CalendarHeatmap
  values={[
    { date: '2016-01-01', count: 1 },
    { date: '2016-01-03', count: 4 },
    { date: '2016-01-06', count: 2 },
    // ...and so on
  ]}
  classForValue={(value) => {
    if (!value) {
      return 'color-empty';
    }
    return `color-scale-${value.count}`;
  }}
/>
```

Then you use CSS to set colors for each class:

```css
.react-calendar-heatmap .color-scale-1 { fill: #d6e685; }
.react-calendar-heatmap .color-scale-2 { fill: #8cc665; }
.react-calendar-heatmap .color-scale-3 { fill: #44a340; }
.react-calendar-heatmap .color-scale-4 { fill: #1e6823; }
```

## Contributing

Take a look at [CONTRIBUTING.md](/CONTRIBUTING.md) to see how to develop on react-calendar-heatmap.

## License

react-calendar-heatmap is Copyright &copy; 2016 PatientsLikeMe, Inc. and is released under an MIT License.  See COPYING for details.