# MongoDB Charts Embedding SDK with React

## Introduction

In the previous blog post of this series, we created a React website that was retrieving a list of countries using Axios and a REST API hosted in MongoDB Realm.

In this blog post, we will continue to build on this foundation and create a dashboard with COVID-19 charts, built with MongoDB Charts and embedded in a React website with the MongoDB Charts Embedding SDK.

To add some spice in the mix, we will use our list of countries to create a dynamic filter so we can filter all the COVID-19 charts by country.

You can see the **final result here** that I hosted in a MongoDB Realm application using the static hosting feature available.

## Prerequisites

The code of this project is available on GitHub in this repository.

```shell
git clone git@github.com:mongodb-developer/mongodb-charts-embedded-react.git
```

To run this project, you will need `node` and `npm` in a recent version. Here is what I'm currently using:

```shell
$ node -v 
v14.17.1
$ npm -v
8.0.0
```

You can run the project locally like so:

```sh
$ cd mongodb-realm-react-charts
$ npm install
$ npm start
```

In the next sections of this blog post, I will explain what we need to do to make this project work.

## Create a MongoDB Charts Dashboard

Before we can actually embed our charts in our custom React website, we need to create them in MongoDB Charts.

Here is the link to the dashboard I created for this website. It looks like this.

If you want to use the same data as me, check out this blog post about the Open Data COVID-19 Project and especially this section to duplicate the data in your own cluster in MongoDB Atlas.

As you can see in the dashboard, my charts are not filtered by country here. You can find the data of all the countries in the four charts I created.

## Enable the Filtering and the Embedding

To enable the filtering when I'm embedding my charts in my website, I must tell MongoDB Charts which field(s) I will be able to filter by, based on the fields available in my collection. Here, I chose to filter by a single field, `country`, and I chose to enable the unauthenticated access for this public blog post (see below).

In the `User Specified Filters` field, I added `country` and chose to use the JavaScript SDK option instead of the iFrame alternative that is less convenient to use for a React website with dynamic filters.

For each of the four charts, I need to retrieve the `Charts Base URL` (unique for a dashboard) and the `Charts IDs`.

Now that we have everything we need, we can go into the React code.

## React Website

### MongoDB Charts Embedding SDK

First things first: We need to install the MongoDB Charts Embedding SDK in our project.

```shell
npm i @mongodb-js/charts-embed-dom
```

It's already done in the project I provided above but it's not if you are following from the first blog post.

### React Project

My React project is made with just two function components: `Dashboard` and `Chart`.

The `index.js` root of the project is just calling the `Dashboard` function component.

```js
import React from 'react';
import ReactDOM from 'react-dom';
import Dashboard from "./Dashboard";

ReactDOM.render(
  
, document.getElementById('root'));
```

The `Dashboard` is the central piece of the project: 

```js
import './Dashboard.css';
import {useEffect, useState} from "react";
import axios from "axios";
import Chart from "./Chart";

const Dashboard = () => {
  const url = 'https://webhooks.mongodb-stitch.com/api/client/v2.0/app/covid-19-qppza/service/REST-API/incoming_webhook/metadata';
  const countries, setCountries] = useState([]);
  const [selectedCountry, setSelectedCountry] = useState("");
  const [filterCountry, setFilterCountry] = useState({});

  function getRandomInt(max) {
    return Math.floor(Math.random() * max);
  }

  useEffect(() => {
    axios.get(url).then(res => {
      setCountries(res.data.countries);
      const randomCountryNumber = getRandomInt(res.data.countries.length);
      let randomCountry = res.data.countries[randomCountryNumber];
      setSelectedCountry(randomCountry);
      setFilterCountry({"country": randomCountry});
    })
  }, [])

  useEffect(() => {
    if (selectedCountry !== "") {
      setFilterCountry({"country": selectedCountry});
    }
  }, [selectedCountry])

  return 
    MongoDB Charts
    COVID-19 Dashboard with Filters
    
      {countries.map(c => 
         setSelectedCountry(c)} checked={c === selectedCountry}/>
        {c}
      )}
    
    
      
      
      
      
    
  
};

export default Dashboard;
```

It's responsible for a few things:

- Line 17 - Retrieve the list of countries from the REST API using Axios (cf [previous blog post).
- Lines 18-22 - Select a random country in the list for the initial value.
- Lines 22 & 26 - Update the filter when a new value is selected (randomly or manually).
- Line 32 `counties.map(...)` - Use the list of countries to build a list of radio buttons to update the filter.
- Line 32 ` x4` - Call the `Chart` component one time for each chart with the appropriate props, including the filter and the Chart ID.

As you may have noticed here, I'm using the same filter `fitlerCountry` for all the Charts, but nothing prevents me from using a custom filter for each Chart.

You may also have noticed a very minimalistic CSS file `Dashboard.css`. Here it is: 

```css
.title {
  text-align: center;
}

.form {
  border: solid black 1px;
}

.elem {
  overflow: hidden;
  display: inline-block;
  width: 150px;
  height: 20px;
}

.charts {
  text-align: center;
}

.chart {
  border: solid #589636 1px;
  margin: 5px;
  display: inline-block;
}
```

The `Chart` component looks like this:

```js
import React, {useEffect, useRef, useState} from 'react';
import ChartsEmbedSDK from "@mongodb-js/charts-embed-dom";

const Chart = ({filter, chartId, height, width}) => {
  const sdk = new ChartsEmbedSDK({baseUrl: 'https://charts.mongodb.com/charts-open-data-covid-19-zddgb'});
  const chartDiv = useRef(null);
  const rendered, setRendered] = useState(false);
  const [chart] = useState(sdk.createChart({chartId: chartId, height: height, width: width, theme: "dark"}));

  useEffect(() => {
    chart.render(chartDiv.current).then(() => setRendered(true)).catch(err => console.log("Error during Charts rendering.", err));
  }, [chart]);

  useEffect(() => {
    if (rendered) {
      chart.setFilter(filter).catch(err => console.log("Error while filtering.", err));
    }
  }, [chart, filter, rendered]);

  return ;
};

export default Chart;
```

The `Chart` component isn't doing much. It's just responsible for rendering the Chart **once** when the page is loaded and reloading the chart if the filter is updated to display the correct data (thanks to React).

Note that the second useEffect (with the `chart.setFilter(filter)` call) shouldn't be executed if the chart isn't done rendering. So it's protected by the `rendered` state that is only set to `true` once the chart is rendered on the screen.

And voilà! If everything went as planned, you should end up with a (not very) beautiful website like [this one.

## Conclusion

In this blog post, your learned how to embed MongoDB Charts into a React website using the MongoDB Charts Embedding SDK.

We also learned how to create dynamic filters for the charts using `useEffect()`.

We didn't learn how to secure the Charts with an authentication token, but you can learn how to do that in this documentation. 

If you have questions, please head to our developer community website where the MongoDB engineers and the MongoDB community will help you build your next big idea with MongoDB.