feat(typing): infer automatically the typing of the generators used i…

…nside of the compose (#358) Co-authored-by: Kamal Bennani <kamal.bennani@aircall.io>
styled-components · Apr 2, 2022 · ecbae73 · ecbae73
1 parent c0c92b4
commit ecbae73
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Showing 2 changed files with 14 additions and 6 deletions.
diff --git a/packages/system/src/style.ts b/packages/system/src/style.ts
@@ -27,6 +27,7 @@ import {
   Mixin,
   StyleOptions,
   CSSOption,
+  StyleGeneratorPropsConcat,
 } from './types'
 
 let themeGetterId = 0
@@ -224,9 +225,14 @@ const sortStyles = (
   return styles
 }
 
-export const compose = <TProps = {}>(
+export function compose<TProps = {}>(
   ...generators: StyleGenerator[]
-): StyleGenerator<TProps> => {
+): StyleGenerator<TProps>
+export function compose<T extends StyleGenerator[]>(
+  ...generators: T
+): StyleGenerator<StyleGeneratorPropsConcat<T>>
+
+export function compose(...generators: any[]): any {
   let flatGenerators: StyleGenerator[] = []
 
   generators.forEach((gen) => {

diff --git a/packages/system/src/types.ts b/packages/system/src/types.ts
@@ -142,8 +142,10 @@ export type ThemeGetterType<T extends ThemeGetter> = T extends ThemeGetter<
   ? T
   : never
 
-export type StyleGeneratorProps<T extends object> = T extends StyleGenerator<
-  infer T
->
-  ? T
+export type StyleGeneratorProps<T> = T extends StyleGenerator<infer Props>
+  ? Props
   : never
+
+export type StyleGeneratorPropsConcat<T> = T extends [infer Head, ...infer Tail]
+  ? StyleGeneratorProps<Head> & StyleGeneratorPropsConcat<Tail>
+  : unknown