Failure to load when Geolocation is disabled in Firefox

Observation

Gets stuck on "Computing ranking."

Console prints "navigator.geolocation is undefined"

Console output

Uncaught (in promise) TypeError: navigator.geolocation is undefined
    geoCheck https://csrankings.org/csrankings.js:1397
    CSRankings https://csrankings.org/csrankings.js:303
    fulfilled https://csrankings.org/csrankings.js:11
    promise callback*step https://csrankings.org/csrankings.js:13
    fulfilled https://csrankings.org/csrankings.js:11
    promise callback*step https://csrankings.org/csrankings.js:13
    fulfilled https://csrankings.org/csrankings.js:11
    promise callback*step https://csrankings.org/csrankings.js:13
    fulfilled https://csrankings.org/csrankings.js:11
    promise callback*step https://csrankings.org/csrankings.js:13
    fulfilled https://csrankings.org/csrankings.js:11
    promise callback*step https://csrankings.org/csrankings.js:13
    __awaiter https://csrankings.org/csrankings.js:14
    __awaiter https://csrankings.org/csrankings.js:10
    CSRankings https://csrankings.org/csrankings.js:287
    CSRankings https://csrankings.org/csrankings.js:340
    <anonymous> https://csrankings.org/csrankings.js:1802

Similar to (but different causes): #718

Steps to Reproduce

Go into about:config in Firefox
Set geo.enabled to false
Visit https://csrankings.org/

Speculated cause

In Firefox, when geo.enabled is set to false, navigator.geolocation returns null.

Although not specified in the MDN API Doc, this behavior is introduced in a commit in 2011.

Possible solution

Surround the following code block with a if "geolocation" in navigator.
Or use optional chaining navigator.geolocation?.getCurrentPosition

CSrankings/csrankings.ts

Lines 1709 to 1726 in c7d9aeb

    
           navigator.geolocation.getCurrentPosition((position) => { 
        
               const continent = whichContinent(position.coords.latitude, position.coords.longitude); 
        
               let regions = (<HTMLInputElement>document.getElementById("regions")); 
        
               switch (continent) { 
        
                   case "northamerica": 
        
                       return; 
        
                   case "europe": 
        
                   case "asia": 
        
                   case "southamerica": 
        
                   case "africa": 
        
                       regions!.value = continent; 
        
                       break; 
        
                   default: 
        
                       regions!.value = "world"; 
        
                       break; 
        
               } 
        
               CSRankings.getInstance().rank(); 
        
           });

	navigator.geolocation.getCurrentPosition((position) => {
	const continent = whichContinent(position.coords.latitude, position.coords.longitude);
	let regions = (<HTMLInputElement>document.getElementById("regions"));
	switch (continent) {
	case "northamerica":
	return;
	case "europe":
	case "asia":
	case "southamerica":
	case "africa":
	regions!.value = continent;
	break;
	default:
	regions!.value = "world";
	break;
	}
	CSRankings.getInstance().rank();
	});