const n = 12697583.9546;
console.log("Locale String: " + n.toLocaleString());
console.log("German: " + n.toLocaleString('de-DE'));
console.log("Arabic: " + n.toLocaleString('ar-EG'));
console.log("Swedish: " + n.toLocaleString('sv-SE'));
console.log("Mainland China: " + n.toLocaleString('zh-CN'));
/*
run:
Locale String: 12,697,583.955
German: 12.697.583,955
Arabic: ١٢٬٦٩٧٬٥٨٣٫٩٥٥
Swedish: 12 697 583,955
Mainland China: 12,697,583.955
*/