Cannot read properties of undefined function in React?

I am creating a weather app using ReactJS. Following is my code:

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      temp: ""
    };
    this.getLocation = this.getLocation.bind(this);
    this.getWeather = this.getWeather.bind(this);
  }
  componentDidMount() {
    this.getLocation();
  }
  getLocation() {
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(success,error);
    }
    else {
      console.log("Not supported");
    }
    function success(position) {
      lat = position.coords.latitude;
      lon = position.coords.longitude;
      console.log(lat,lon);
      this.getWeather();
    }
    function error() {
      console.log("Unable to retrieve your location");
    }
  }
  getWeather() {
    fetch(`http://api.weatherapi.com/v1/current.json?key=${api}&q=${lat},${lon}&aqi=no`)
    .then((data) => data.json())
    .then((item) => {
      console.log(item);
    });
  }

api, lat and lon are constants I declared and initialized before this. This is giving the error:

Cannot read properties of undefined (reading 'getWeather')
    at success

function success(position) {
      lat = position.coords.latitude;
      lon = position.coords.longitude;
      console.log(lat,lon);
      this.getWeather();
    }

this here refers to the success function scope

use arrow function

success=(position)=>{
      lat = position.coords.latitude;
      lon = position.coords.longitude;
      console.log(lat,lon);
      this.getWeather();
}

or modify the whole code to

 getLocation() {
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(success,error);
    }
    else {
      console.log("Not supported");
    }
    const that = this; // now variable 'that' has the reference of 'this'
    function success(position) {
      lat = position.coords.latitude;
      lon = position.coords.longitude;
      console.log(lat,lon);
      that.getWeather();
    }
    function error() {
      console.log("Unable to retrieve your location");
    }
  }