Using mapbox-gl in React with Next.js

Introduction

In this article I want to describe the ways I know of embedding mapbox-gl in aReact application, using the example of creating a simple web application containing a map on Next.js using Typescript, the map component code can also be used in any React application

This article is part of a series of articles

I will consider several implementation options using the example of creating a functional map component:

Implementation with keep the map instance inside the React component
Keeping the map instance outside of React

Code snippets info

For comfortable reading of this article, you need to have
basic knowledge of React,Typescript and CSS

All code snippets will be using Typescript, using typing
in javascript is the best practice, so I basically stick to
it where possible, I apologize if you are not familiar with
it, here is a great course from egghead.io where you can read it

I prefer to import React as import * as React from "react" you can read more about this in
great article by Kent C. Dodds

If // ... is encountered in the code, it must be read as
places with missing duplicate code

Preparing the environment

First of all, let's create a new project in Next.js using the Typescript template.

npx create-next-app --typescript my-awesome-app

Let's open the project folder and install the mapbox-gl with types for Typescript

cd my-awesome-app

npm install --save mapbox-gl && npm install -D @type/mapbox-gl

We also need accessToken for mapbox-gl, from environment variable so as not to store it directly in the source code

touch .env.local
echo NEXT_PUBLIC_MAPBOX_TOKEN=<your_token> >> .env.local

This is how your file should look like with environment variable for Next.js

.env.local

NEXT_PUBLIC_MAPBOX_TOKEN=<your_token>

Implementation as a functional `React` component

Preparing styles

Remove unnecessary styles and update the global stylesheet

rm styles/Home.module.css

styles / global.css

html,
body,
#__next {
  padding: 0;
  margin: 0;
  width: 100%;
  height: 100%;
}

* {
  box-sizing: border-box;
}

To make the height of the application equal to 100% of the window height, set the properties width and height to 100% for html and body

The height must also be specified for the element with the css selector#__ next because in the Next.js application the root element is<div id = "__ next"> ... </div>

Preparing a map component

components/mapbox-map.tsx

import * as React from "react";
import mapboxgl from "mapbox-gl";
import "mapbox-gl/dist/mapbox-gl.css"; 
// import the mapbox-gl styles so that the map is displayed correctly

function MapboxMap() {
    // this is where the map instance will be stored after initialization
  const [map, setMap] = React.useState<mapboxgl.Map>();

    // React ref to store a reference to the DOM node that will be used
  // as a required parameter `container` when initializing the mapbox-gl
  // will contain `null` by default
    const mapNode = React.useRef(null);

  React.useEffect(() => {
    const node = mapNode.current;
        // if the window object is not found, that means
        // the component is rendered on the server
        // or the dom node is not initialized, then return early
    if (typeof window === "undefined" || node === null) return;

        // otherwise, create a map instance
    const mapboxMap = new mapboxgl.Map({
      container: node,
            accessToken: process.env.NEXT_PUBLIC_MAPBOX_TOKEN,
            style: "mapbox://styles/mapbox/streets-v11",
      center: [-74.5, 40],
      zoom: 9,
    });

        // save the map object to React.useState
    setMap(mapboxMap);

        return () => {
      mapboxMap.remove();
    };
  }, []);

    return <div ref={mapNode} style={{ width: "100%", height: "100%" }} />;
}

export default MapboxMap

Description of the mapbox-gl init parameters can be found in the documentation

Next, we import it to the main page of the application and launch the project

pages/index.tsx

import MapboxMap from "../components/mapbox-map";

function App() {
  return <MapboxMap />;
}

export default App;

npm run dev

Opening http://localhost:3000 we see a full-screen web map

What Can Be Done Better

The proposed implementation is missing several useful features.

Map initialization parameters - when using a map component, it seems useful to be able to pass initial map options through the props
Access to the map instance from other components - the application usually contains other components for which you need to have access directly to the map instance
Map ready callback - loading the map takes some time, while the user is waiting for the opening of the map, to improve the user experience, you can show a skeleton or loading screen with a spinner. For these purposes, it would be convenient to have a callback triggered after the map is fully loaded.

An example with loading a map in my application https://app.mapflow.ai

Improving map component

Let's implement all these features, first add the props for the MapboxMap component

The container property of the MapboxOptions interface is not required in this case, to exclude it we use the utility type Omit

Let's pass initialOptions to the web map init options using spread syntax, we will also set a callback for the map load event

// ...
    const mapboxMap = new mapboxgl.Map({
      container: node,
      accessToken: process.env.NEXT_PUBLIC_MAPBOX_TOKEN,
      style: "mapbox://styles/mapbox/streets-v11",
      center: [-74.5, 40],
      zoom: 9,
      ...initialOptions,
    });

    setMap(mapboxMap);

        // if onMapLoaded is specified it will be called once
    // by "load" map event
    if (onMapLoaded) mapboxMap.once("load", onMapLoaded);

        // removing map object and calling onMapRemoved callback
    // when component will unmout 
        return () => {
      mapboxMap.remove();
      if (onMapRemoved) onMapRemoved();
    };

    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

// ...

Here you can see a special comment for the linter

// eslint-disable-next-line react-hooks/exhaustive-deps

According to react-hooks/exhaustive-deps rule we had to specify in the list of dependencies for React.useEffect variables added to the hook [initialOptions, onMapLoaded]

In this case, it is important to leave dependency list empty, this will allow you not to re-create the map instance if initialOptions or onMapLoaded was changed, you can read more about using React.useEffect at the link below

Final component version will look like this

components/mapbox-map.tsx

import * as React from "react";
import mapboxgl from "mapbox-gl";
import "mapbox-gl/dist/mapbox-gl.css";

interface MapboxMapProps {
  initialOptions?: Omit<mapboxgl.MapboxOptions, "container">;
  onMapLoaded?(map: mapboxgl.Map): void;
    onMapRemoved?(): void;
}

function MapboxMap({ initialOptions = {}, onMapLoaded }: MapboxMapProps) {
  const [map, setMap] = React.useState<mapboxgl.Map>();

  const mapNode = React.useRef(null);

  React.useEffect(() => {
    const node = mapNode.current;

    if (typeof window === "undefined" || node === null) return;

    const mapboxMap = new mapboxgl.Map({
      container: node,
      accessToken: process.env.NEXT_PUBLIC_MAPBOX_TOKEN,
      style: "mapbox://styles/mapbox/streets-v11",
      center: [-74.5, 40],
      zoom: 9,
      ...initialOptions,
    });

    setMap(mapboxMap);

    if (onMapLoaded) mapboxMap.once("load", onMapLoaded);

        return () => {
      mapboxMap.remove();
      if (onMapRemoved) onMapRemoved();
    };

    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return <div ref={mapNode} style={{ width: "100%", height: "100%" }} />;
}

export default MapboxMap;

Now we can override the initial map properties and use the onMapLoaded callback when it is loaded. We can also use onMapLoaded to store a link to the map instance in the parent component, for example. We can also use onMapRemoved if we need to know that the map instance has been removed.

We will use this, to define the coordinates of the center of the map, and also add the initial screen for loading the map.

First, let's prepare a MapLoadingHolder component that will be displayed on top of the map until it is loaded.

Let's use a svg icon for the loading screen. I have it from https://www.freepik.com, and then converted it to jsx format using https://svg2jsx.com/

components/world-icon.tsx

function WorldIcon({ className = "" }: { className?: string }) {
  return (
    <svg
      className={className}
      xmlns="http://www.w3.org/2000/svg"
      width="48.625"
      height="48.625"
      x="0"
      y="0"
      enableBackground="new 0 0 48.625 48.625"
      version="1.1"
      viewBox="0 0 48.625 48.625"
      xmlSpace="preserve"
    >
      <path d="M35.432 10.815L35.479 11.176 34.938 11.288 34.866 12.057 35.514 12.057 36.376 11.974 36.821 11.445 36.348 11.261 36.089 10.963 35.7 10.333 35.514 9.442 34.783 9.591 34.578 9.905 34.578 10.259 34.93 10.5z"></path>
      <path d="M34.809 11.111L34.848 10.629 34.419 10.444 33.819 10.583 33.374 11.297 33.374 11.76 33.893 11.76z"></path>
      <path d="M22.459 13.158l-.132.34h-.639v.33h.152l.022.162.392-.033.245-.152.064-.307.317-.027.125-.258-.291-.06-.255.005z"></path>
      <path d="M20.812 13.757L20.787 14.08 21.25 14.041 21.298 13.717 21.02 13.498z"></path>
      <path d="M48.619 24.061a24.552 24.552 0 00-.11-2.112 24.165 24.165 0 00-1.609-6.62c-.062-.155-.119-.312-.185-.465a24.341 24.341 0 00-4.939-7.441 24.19 24.19 0 00-1.11-1.086A24.22 24.22 0 0024.312 0c-6.345 0-12.126 2.445-16.46 6.44a24.6 24.6 0 00-2.78 3.035A24.18 24.18 0 000 24.312c0 13.407 10.907 24.313 24.313 24.313 9.43 0 17.617-5.4 21.647-13.268a24.081 24.081 0 002.285-6.795c.245-1.381.379-2.801.379-4.25.001-.084-.004-.167-.005-.251zm-4.576-9.717l.141-.158c.185.359.358.724.523 1.094l-.23-.009-.434.06v-.987zm-3.513-4.242l.004-1.086c.382.405.75.822 1.102 1.254l-.438.652-1.531-.014-.096-.319.959-.487zM11.202 7.403v-.041h.487l.042-.167h.797v.348l-.229.306h-1.098l.001-.446zm.778 1.085s.487-.083.529-.083 0 .486 0 .486l-1.098.069-.209-.25.778-.222zm33.612 9.651h-1.779l-1.084-.807-1.141.111v.696h-.361l-.39-.278-1.976-.501v-1.28l-2.504.195-.776.417h-.994l-.487-.049-1.207.67v1.261l-2.467 1.78.205.76h.5l-.131.724-.352.129-.019 1.892 2.132 2.428h.928l.056-.148h1.668l.481-.445h.946l.519.52 1.41.146-.187 1.875 1.565 2.763-.824 1.575.056.742.649.647v1.784l.852 1.146v1.482h.736c-4.096 5.029-10.33 8.25-17.305 8.25C12.009 46.625 2 36.615 2 24.312c0-3.097.636-6.049 1.781-8.732v-.696l.798-.969c.277-.523.574-1.033.891-1.53l.036.405-.926 1.125a22.14 22.14 0 00-.798 1.665v1.27l.927.446v1.765l.889 1.517.723.111.093-.52-.853-1.316-.167-1.279h.5l.211 1.316 1.233 1.799-.318.581.784 1.199 1.947.482v-.315l.779.111-.074.556.612.112.945.258 1.335 1.521 1.705.129.167 1.391-1.167.816-.055 1.242-.167.76 1.688 2.113.129.724s.612.166.687.166c.074 0 1.372.983 1.372.983v3.819l.463.13-.315 1.762.779 1.039-.144 1.746 1.029 1.809 1.321 1.154 1.328.024.13-.427-.976-.822.056-.408.175-.5.037-.51-.66-.02-.333-.418.548-.527.074-.398-.612-.175.036-.37.872-.132 1.326-.637.445-.816 1.391-1.78-.316-1.392.427-.741 1.279.039.861-.682.278-2.686.955-1.213.167-.779-.871-.279-.575-.943-1.965-.02-1.558-.594-.074-1.111-.52-.909-1.409-.021-.814-1.278-.723-.353-.037.39-1.316.078-.482-.671-1.373-.279-1.131 1.307-1.78-.302-.129-2.006-1.299-.222.521-.984-.149-.565-1.707 1.141-1.074-.131-.383-.839.234-.865.592-1.091 1.363-.69 2.632-.001-.007.803.946.44-.075-1.372.682-.686 1.376-.904.094-.636 1.372-1.428 1.459-.808-.129-.106.988-.93.362.096.166.208.375-.416.092-.041-.411-.058-.417-.139v-.4l.221-.181h.487l.223.098.193.39.236-.036v-.034l.068.023.684-.105.097-.334.39.098v.362l-.362.249h.001l.053.397 1.239.382.003.015.285-.024.019-.537-.982-.447-.056-.258.815-.278.036-.78-.852-.519-.056-1.315-1.168.574h-.426l.112-1.001-1.59-.375-.658.497v1.516l-1.183.375-.474.988-.514.083v-1.264l-1.112-.154-.556-.362-.224-.819 1.989-1.164.973-.296.098.654.542-.028.042-.329.567-.081.01-.115-.244-.101-.056-.348.697-.059.421-.438.023-.032.005.002.128-.132 1.465-.185.648.55-1.699.905 2.162.51.28-.723h.945l.334-.63-.668-.167v-.797l-2.095-.928-1.446.167-.816.427.056 1.038-.853-.13-.131-.574.817-.742-1.483-.074-.426.129-.185.5.556.094-.111.556-.945.056-.148.37-1.371.038s-.038-.778-.093-.778l1.075-.019.817-.798-.446-.223-.593.576-.984-.056-.593-.816h-1.261l-1.316.983h1.206l.11.353-.313.291 1.335.037.204.482-1.503-.056-.073-.371-.945-.204-.501-.278-1.125.009A22.188 22.188 0 0124.312 2c5.642 0 10.797 2.109 14.73 5.574l-.265.474-1.029.403-.434.471.1.549.531.074.32.8.916-.369.151 1.07h-.276l-.752-.111-.834.14-.807 1.14-1.154.181-.167.988.487.115-.141.635-1.146-.23-1.051.23-.223.585.182 1.228.617.289 1.035-.006.699-.063.213-.556 1.092-1.419.719.147.708-.64.132.5 1.742 1.175-.213.286-.785-.042.302.428.483.106.566-.236-.012-.682.251-.126-.202-.214-1.162-.648-.306-.861h.966l.309.306.832.717.035.867.862.918.321-1.258.597-.326.112 1.029.583.64 1.163-.02c.225.579.427 1.168.604 1.769l-.121.112zm-32.331-7.093l.584-.278.528.126-.182.709-.57.181-.36-.738zm3.099 1.669v.459h-1.334l-.5-.139.125-.32.641-.265h.876v.265h.192zm.614.64v.445l-.334.215-.416.077v-.737h.75zm-.376-.181v-.529l.459.418-.459.111zm.209 1.07v.433l-.319.32h-.709l.111-.486.335-.029.069-.167.513-.071zm-1.766-.889h.737l-.945 1.321-.39-.209.084-.556.514-.556zm3.018.737v.432h-.709l-.194-.28v-.402h.056l.847.25zm-.655-.594l.202-.212.341.212-.273.225-.27-.225zm28.55 5.767l.07-.082c.029.126.06.252.088.38l-.158-.298z"></path>
      <path d="M3.782 14.884v.696c.243-.568.511-1.122.798-1.665l-.798.969z"></path>
    </svg>
  );
}

export default WorldIcon;

components/map-loading-holder.tsx

import WorldIcon from "../components/world-icon";

function MapLoadingHolder() {
  return (
    <div className="loading-holder">
      <WorldIcon className="icon" />
      <h1>Initializing the map</h1>
      <div className="icon-attribute">
        Icons made by{" "}
        <a href="https://www.freepik.com" title="Freepik">
          Freepik
        </a>{" "}
        from{" "}
        <a href="https://www.flaticon.com/" title="Flaticon">
          www.flaticon.com
        </a>
      </div>
    </div>
  );
}

export default MapLoadingHolder;

Now, putting everything together, put the application in an .app-container element, inside which there will be an absolutely positioned map element placed in a map-wrapper and a MapLoadingHolder component

Let's also add the <Head> ... </Head> component, you can specify meta tags and title for the site with it

Let's make the changes to the styles, add a nice background for the .loading-holder, also align its content in the center, add a pulsing animation for the icon, since the background is semi-transparent, add a colored shadow text-shadow: 0px 0px 10px rgba (152, 207, 195 , 0.7); to the element <h1>Initializing the map</h1>

Now when we open the map we will see a nice loading screen