How to convert the first letter of a string literal type into an uppercase format or capitalize in TypeScript?
Published February 10, 2022
To convert the first letter of string literal type into an uppercase format or capitalize, you can use the built-in Capitalize
type that comes with TypeScript.
TL;DR
// string literal type
type Greeting = "hello";
// convert first letter of
// string literal type
// into uppercase format or capitalize
type GreetingCapitalized = Capitalize<Greeting>; // Hello
For example, let's say we have a string literal type like this,
// string literal type
type Greeting = "hello";
Now to capitalize the string literal type let's use the Capitalize
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 = "hello";
// convert first letter of
// string literal type
// into uppercase format or capitalize
type GreetingCapitalized = Capitalize<Greeting>; // Hello
Now if you hover over the GreetingCapitalized
type you can see that the hello
string literal type is now capitalized. Yay 🥳.
See the above code live in codesandbox.
That's all 😃!