I think the function toLocaleDateString use the default local data on the device.
try this code to check the output:
// America/Los_Angeles for the US
// US English uses month-day-year order
console.log(date.toLocaleDateString('en-US'));
// → "12/19/2012"
// British English uses day-month-year order
console.log(date.toLocaleDateString('en-GB'));
// → "20/12/2012"
// Korean uses year-month-day order
console.log(date.toLocaleDateString('ko-KR'));
// → "2012. 12. 20."
// Arabic in most Arabic speaking countries uses real Arabic digits
console.log(date.toLocaleDateString('ar-EG'));
// → "٢٠/١٢/٢٠١٢"
// chinese
console.log(date.toLocaleDateString('zh-Hans-CN'));
// → "2012/12/20"