toLocaleString is a built-in JavaScript method used to convert the date and time to a string using the system locales. 🤓🚀

It can be used with the following JavaScript types 💪:

• Dates/Time
• Numbers
• Objects
• Arrays

toLocaleString with Dates and Time 🚀

With dates/time objects, toLocaleString has a syntax like this and returns a string 🔥👉:

dateObject.toLocaleString(locales, options)

• locales: An optional string that specifies a language-specific format. Some valid values are ar-SA (for Arabic), en-US (for US English), hi-IN (for Hindi), jp-JP (for Japanese), etc.
• options: An optional object of options. Some valid properties that can be included in this are dateStyle with values of full, long, medium and short. Other possible properties are timeStyle, weekday, year, month, day, hour, minute, second, etc.

Example 😍

const date = new Date();

console.log(date.toLocaleString(`en-US`)); 
// 11/10/2019, 4:32:44 PM

console.log(date.toLocaleString(`hi-IN`));
// 10/11/2019, 4:32:44 pm

console.log(date.toLocaleString(`fr-CH`));
// 10.11.2019 à 16:32:44

const options = {
  weekday: 'long',
  era: 'long'
}

console.log(date.toLocaleString(`en-US`, options)); 
// Sunday Anno Domini

console.log(date.toLocaleString(`hi-IN`, options));
// ईसवी सन रविवार

console.log(date.toLocaleString(`fr-CH`, options));
// après Jésus-Christ dimanche

toLocaleString with Numbers 🚀

With numbers, toLocaleString is used to convert the numbers into a locale-specific number representation. It has syntax something like the following and returns a string 🔥👉:

number.toLocaleString(locales, options)

• locales: An optional string the specifies the locale.
• options: An optional object that can contain properties such as localeMatcher with values lookup and best fit. Other valied properties are style, currency, useGrouping, minimumSignificantDigits, etc.

Example 😍

const number = 12345.678;

console.log(number.toLocaleString('en-US')); 
// 12,345.678

console.log(number.toLocaleString('fr-FR')); 
// 12 345,678

console.log(number.toLocaleString('en-US', {
  style: 'currency',
  currency: 'USD'   // With currency, the currency code is also required
}));  // $12,345.68

console.log(number.toLocaleString('hi-IN', {
  style: 'currency',
  currency: 'INR'
}));  // ₹12,345.68

console.log(number.toLocaleString('en-US', {
  style: 'currency',
  currency: 'USD',
  maximumSignificantDigits: 2
}));  // $12,000

toLocaleString with Arrays 🚀

With arrays, toLocaleString is used to convert them into a locale-specific representation. The syntax is as follows and once again a string is returned 🔥👉:

array.toLocaleString(locales, options)

• locales: An optional string specifying the locale.
• options: An optional object of the same options available to numbers and dates.

Example 😍

const arr = [12345678, new Date(), "alligators"];
console.log(arr.toLocaleString(`fr-FR`,{
  style: 'currency',
  currency: 'EUR',
  era: 'long'
}));

//  12 345 678,00 €,10 11 2019 après Jésus-Christ à 18:30:03,alligators

const arr2 = [12345678, new Date(), "alligators"];
console.log(arr.toLocaleString(`en-US`,{
  style: 'currency',
  currency: 'USD',
  era: 'long'
}));

//  $12,345,678.00,11 10, 2019 Anno Domini, 6:31:56 PM,alligators

Note: If locale is omitted or left undefined than the default system locale is used. 🧪

🥓 Now what’s left is to make sure your targeted browsers support the toLocaleString method.