To convert a string literal type into a lowercase format, you can use the built-in Lowercase type that comes with TypeScript.
TL;DR
// string literal type
type Greeting = "Hi, How Are you?";
// convert string literal type
// into lowercase format
type GreetingLowercase = Lowercase<Greeting>; // hi, how are you?
For example, let's say we have a string literal type like this,
// string literal type
type Greeting = "Hi, How Are you?";
Now to convert the string literal type into lowercase let's use the Lowercase built-in type and pass the Greeting type into it using the angled bracket (<>) syntax.
It can be done like this,
// string literal type
type Greeting = "Hi, How Are you?";
// convert string literal type
// into lowercase format
type GreetingLowercase = Lowercase<Greeting>; // hi, how are you?
Now if you hover over the GreetingLowercase type you can see that the Hi, How Are you? string literal type is now converted into a lowercase format. Yay 🥳.
See the above code live in codesandbox.
That's all 😃!