Template Literal Types support

[johnsoncodehk]

TypeScript 4.1 supports more string type variants, please see: microsoft/TypeScript#40336

It can be used to improve the type inference of props / emits... to help IDE typecheck. Backward compatibility is a problem, but we can consider use to defineComponent in future.

Playground

type uncapitalize = Uncapitalize<'FooBarBax'> // 'forBarBaz'
type hyphenate = Hyphenate<uncapitalize> // 'for-bar-baz'
type camelize = Camelize<hyphenate> // 'forBarBaz'
type capitalize = Capitalize<camelize> // 'FooBarBax'

type Hyphenate<S> = S extends `${infer T}${infer U}` ? T extends Uppercase<T> ? `-${Lowercase<T>}${Hyphenate<U>}` : `${T}${Hyphenate<U>}` : S;
type Camelize<S> = S extends `${infer T}-${infer U}` ? `${T}${Camelize<Capitalize<U>>}` : S;

[znck]

cc @pikax

[pikax]

Some work already wok the works to add for emit and events, i can add for props too

vuejs/core#2164

[johnsoncodehk]

The closure has been implemented.