Can not read property 'state' of undefined in react nested useState hooks - reactjs

Question

I am trying to convert this class based to functional component based
here is the actual CLASS BASED CODE
import React, { Component } from 'react';
import L from 'leaflet'
import { Map, TileLayer, Marker, Popup } from 'react-leaflet';
import './App.css';
// Icon properties
var myIcon = L.icon({
iconUrl: 'data:image/png;base64,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',
iconSize: [25, 41],
iconAnchor: [22, 94],
popupAnchor: [-10, -90],
});
export default class Fullmap extends Component {
state = {
location: {
lat: 51.097,
lng: -1.505
},
haveUsersLocation: false,
zoom: 2
}
componentDidMount(){
// Get GeoLocation for setting marker from browser on page load
navigator.geolocation.getCurrentPosition((position) =>{
this.setState({
location:{
lat: position.coords.latitude,
lng: position.coords.longitude
},
haveUsersLocation: true,
zoom: 13
});
}, ()=>{
// If denied location via browser, get via IP
fetch('https://ipapi.co/json')
.then(res => res.json())
.then(location =>{
this.setState({
location:{
lat: location.latitude,
lng: location.longitude
},
haveUsersLocation: true,
zoom: 13
});
})
});
}
render(){
const position = [this.state.location.lat, this.state.location.lng];
return (
<div className="App">
<Map className="Map" center={position} zoom={this.state.zoom}>
<TileLayer
attribution='&copy OpenStreetMap contributors'
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
{this.state.haveUsersLocation ?
<Marker
icon={myIcon}
position={position}>
<Popup>
A pretty CSS3 popup. <br /> Easily customizable.
</Popup>
</Marker> : ''
}
</Map>
</div>
);
}
}
This is working fine with no error whereas now when i converted it to below functional based code
import React, { useState, useEffect } from 'react';
import L from 'leaflet'
import { Map, TileLayer, Marker, Popup } from 'react-leaflet';
import './App.css';
// Icon properties
var myIcon = L.icon({
iconUrl: 'data:image/png;base64,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',
iconSize: [25, 41],
iconAnchor: [22, 94],
popupAnchor: [-10, -90],
});
export default function MyMap() {
const [location, setLocation] = useState({
lat: false,
lng: null,
zoom: 2,
usersLocation: false
});
useEffect(() => {
// Get GeoLocation for setting marker from browser on page load
navigator.geolocation.getCurrentPosition((position) =>{
setLocation([...location,{
lat: position.coords.latitude,
lng: position.coords.longitude,
haveUsersLocation: true,
zoom: 13
}]);
}, ()=>{
// If denied location via browser, get via IP
fetch('https://ipapi.co/json')
.then(res => res.json())
.then(location =>{
setLocation([...location,{
lat: location.coords.latitude,
lng: location.coords.longitude,
haveUsersLocation: true,
zoom: 13
}]);
})
});
});
const position = [location.lat, location.lng];
return (
<div className="App">
<Map className="Map" center={position} zoom={location.zoom}>
<TileLayer
attribution='&copy OpenStreetMap contributors'
url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
/>
{this.state.haveUsersLocation ?
<Marker
icon={myIcon}
position={position}>
<Popup>
A pretty CSS3 popup. <br /> Easily customizable.
</Popup>
</Marker> : ''
}
</Map>
</div>
);
}
it is giving me error as TypeError: Cannot read property 'state' of undefined on Line No. 54
I would really appreciate if you could help me point out my error and also explain a bit as I'm pretty new to react.

Answer 1

A functional component doesn't have a this to access the state. You can just reference the state variables directly, in your case location
To expand:
in a class component this refers to the class instance, where the state is stored. In a functional component you gain access to the state via the state variable returned from the useState hook

Answer 2

Only class components have access to this. if you would like to get the current state of haveUsersLocation just simply use location.haveUsersLocation

Answer 3

instead of
{this.state.haveUsersLocation ?
<Marker
...
}
use
{location.haveUsersLocation ?
<Marker
...
}
you have used useState const [location, setLocation] = useState so you can get updated state directly from location variable.