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javascriptleafletnext.jsreact-leaflet

Leaflet with next.js?


I am getting a ReferenceError:

window is not defined when using next.js with leaflet.js .

Wondering if there's a simple solution to this problem - is using next.js overcomplicating my workflow?

for those curious with the exact code,

import React, { createRef, Component } from "react";
import L from "leaflet";
import { Map, TileLayer, Marker, Popup, DivOverlay } from "react-leaflet";
import axios from "axios";
import Header from "./Header";


export default class PDXMap extends Component {
  state = {
    hasLocation: false,
    latlng: {
      lat: 45.5127,
      lng: -122.679565
    },
    geoJSON: null
  };

  mapRef = createRef();

  componentDidMount() {
    this.addLegend();
    if (!this.state.hasLocation) {
      this.mapRef.current.leafletElement.locate({
        setView: true
      });
    }
    axios
      .get(
        "https://opendata.arcgis.com/datasets/40151125cedd49f09d211b48bb33f081_183.geojson"
      )
      .then(data => {
        const geoJSONData = data.data;
        this.setState({ geoJSON: geoJSONData });
        return L.geoJSON(this.state.geoJSON).addTo(
          this.mapRef.current.leafletElement
        );
      });
  }

  handleClick = () => {
    this.mapRef.current.leafletElement.locate();
  };

  handleLocationFound = e => {
    console.log(e);
    this.setState({
      hasLocation: true,
      latlng: e.latlng
    });
  };

  getGeoJsonStyle = (feature, layer) => {
    return {
      color: "#006400",
      weight: 10,
      opacity: 0.5
    };
  };

  addLegend = () => {
    const map = this.mapRef.current.leafletElement;
    L.Control.Watermark = L.Control.extend({
      onAdd: function(map) {
        var img = L.DomUtil.create("img");

        img.src = "https://leafletjs.com/docs/images/logo.png";
        img.style.width = "200px";

        return img;
      }
    });

    L.control.watermark = function(opts) {
      return new L.Control.Watermark(opts);
    };

    L.control.watermark({ position: "bottomleft" }).addTo(map);
  };

  render() {
    const marker = this.state.hasLocation ? (
      <Marker position={this.state.latlng}>
        <Popup>
          <span>You are here</span>
        </Popup>
      </Marker>
    ) : null;

    return (
      <Map
        className="map-element"
        center={this.state.latlng}
        length={4}
        onClick={this.handleClick}
        setView={true}
        onLocationfound={this.handleLocationFound}
        ref={this.mapRef}
        zoom={14}
      >
        <TileLayer
          attribution='&amp;copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
          url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
        />
        {marker}
      </Map>
    );
  }
}

/**
 * TODO:  Add Header + Legend to map
 *        - Header to be styled
 *        - Legend to be present in header
 *
 */


import React from 'react';
import PDXMap from "../components/map";


export default function SignIn() {
  const classes = useStyles();

  return (
      <PDXMap/>
);
}

I'm happy to use any way forward - just interested in getting a functional product.

Cheers!

Update

Hey everyone,

I am still getting this error (came back to this a bit later than I had planned haha).

I am currently using this approach with useEffects,

import React, {useEffect, useState} from 'react';

function RenderCompleted() {

    const [mounted, setMounted] = useState(false);

    useEffect(() => {
        setMounted(true)

        return () => {
            setMounted(false)
        }
    });

    return mounted;
}

export default RenderCompleted;

and this is the page it is showing on

import React, { useEffect } from "react";
import Router, { useRouter } from "next/router";
import { useRef, useState } from "react";


//viz
import PDXMap from "../../components/Visualization/GIS/map";

import RenderCompleted from "../../components/utils/utils";

// import fetch from 'isomorphic-unfetch';
import { Cookies, CookiesProvider } from "react-cookie";
const cookies = new Cookies();
//containers

// Layouts
import Layout from "../../components/Layout/Layout_example";
import Chart from "../../components/Visualization/Graphs/Chart";
import Table from "../../components/Visualization/Tables/Table";
import Sidebar from "../../components/Layout/Sidebar/SidebarProperty";



export default function Bargains() {

  // const [inbrowser, setBrowser] = useState(false);

  const choiceRef = useRef<any>();
  const [message, setMessage] = useState<any>(null);

  const [productList, setProductList] = useState<any>([]);
  const [searched, setSearched] = useState(false);

  const router = useRouter();

  let token = cookies.get("token");

  // useEffect(() => {
  //   setBrowser(true);
  // });
  const isMounted = RenderCompleted();


  const columns = React.useMemo(
    () => [
    ....
    ],

    []
  )



  async function handleChoice() {

    console.log("searching...", choiceRef.current?.value);
    setMessage("Searching...");
    var headers = {
      "Content-Type": "application/x-www-form-urlencoded",
      "auth-token": token,
    };

    fetch(
    ....
  }


            <div className="flex flex-wrap ">
            {isMounted && <PDXMap/>}


              
              <Table columns={columns as any} data={productList as any} />


            </div>
          </div>



        </div>
      </div>


    </Layout>



  )
}

With the same error message of

ReferenceError: window is not defined

##update two

Okay, so oddly, it does work when I browse into the site from another page, but not when i load the page itself.

Will have a think on this, but perhaps it is because the map is loading data with componentDidMount() and that is interacting weirdly?

Update

Okay I've created a more simple example based on https://github.com/rajeshdh/react-leaflet-with-nextjs

Now it is loading, but the tiles are showing incorrectly, with some tiles not loading.

This is the map component I am using to be simple,

import React, { Component, createRef } from 'react';
import { Map, TileLayer, Marker, Popup, MapControl, withLeaflet } from 'react-leaflet';
import { GeoSearchControl, OpenStreetMapProvider } from 'leaflet-geosearch';


class SearchBox extends MapControl {
  constructor(props) {
    super(props);
    props.leaflet.map.on('geosearch/showlocation', (e) => props.updateMarker(e));
  }

  createLeafletElement() {
    const searchEl = GeoSearchControl({
      provider: new OpenStreetMapProvider(),
      style: 'bar',
      showMarker: true,
      showPopup: false,
      autoClose: true,
      retainZoomLevel: false,
      animateZoom: true,
      keepResult: false,
      searchLabel: 'search'
    });
    return searchEl;
  }
}


export default class MyMap extends Component {
  state = {
    center: {
      lat: 31.698956,
      lng: 76.732407,
    },
    marker: {
      lat: 31.698956,
      lng: 76.732407,
    },
    zoom: 13,
    draggable: true,
  }

  refmarker = createRef(this.state.marker)

  toggleDraggable = () => {
    this.setState({ draggable: !this.state.draggable });
  }

  updateMarker = (e) => {
    // const marker = e.marker;
    this.setState({
      marker: e.marker.getLatLng(),
    });
    console.log(e.marker.getLatLng());
  }

  updatePosition = () => {
    const marker = this.refmarker.current;
    if (marker != null) {
      this.setState({
        marker: marker.leafletElement.getLatLng(),
      });
    }
    console.log(marker.leafletElement.getLatLng());
  }

  render() {
    const position = [this.state.center.lat, this.state.center.lng];
    const markerPosition = [this.state.marker.lat, this.state.marker.lng];
    const SearchBar = withLeaflet(SearchBox);

    return (
      <div className="map-root">
        <Map center={position} zoom={this.state.zoom} style={{
                        height:"700px"
                    }}>
          <TileLayer
            attribution='&amp;copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
            url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
          />
          <Marker
            draggable={true}
            onDragend={this.updatePosition}
            position={markerPosition}
            animate={true}
            ref={this.refmarker}>
            <Popup minWidth={90}>
              <span onClick={this.toggleDraggable}>
                {this.state.draggable ? 'DRAG MARKER' : 'MARKER FIXED'}
              </span>
            </Popup>
          </Marker>
          <SearchBar updateMarker={this.updateMarker} />
        </Map>
        <style jsx>{`
                .map-root {
                  height: 100%;
                }
                .leaflet-container {
                 height: 400px !important;
                 width: 80%;
                 margin: 0 auto;
               }
           `}
        </style>
      </div>
    );
  }
}

And to call it, I am using this:

const SimpleExample = dynamic(() => import("../../components/Visualization/GIS/map"), {
  ssr: false
}); 

And have tried this:

{isMounted && <SimpleExample/>}

Solution

  • window is not available in SSR, you probably get this error on your SSR env.

    One way to solve this is to mark when the component is loaded in the browser (by using componentDidMount method), and only then render your window required component.

    class MyComp extends React.Component {
      state = {
        inBrowser: false,
      };
    
      componentDidMount() {
        this.setState({ inBrowser: true });
      }
    
      render() {
        if (!this.state.inBrowser) {
          return null;
        }
    
        return <YourRegularComponent />;
      }
    }
    

    This will work cause componentDidMount lifecycle method is called only in the browser.

    Edit - adding the "hook" way

    import { useEffect, useState } from 'react';
    
    const MyComp = () => {
      const [isBrowser, setIsBrowser] = useState(false);
      useEffect(() => {
        setIsBrowser(true);
      }, []);
    
      if (!isBrowser) {
        return null;
      }
    
      return <YourRegularComponent />;
    };
    

    useEffect hook is an alternative for componentDidMount which runs only inside the browser.