fix: improve types

codsen · May 3, 2022 · 53262e1 · 53262e1
1 parent 9157fe2
commit 53262e1
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Showing 4 changed files with 24 additions and 19 deletions.
diff --git a/packages/arrayiffy-if-string/README.md b/packages/arrayiffy-if-string/README.md
@@ -62,4 +62,6 @@ MIT License
 
 Copyright (c) 2010-2022 Roy Revelt and other contributors
 
+Thanks to KRyan for types https://stackoverflow.com/a/71834598/3943954
+
 <img src="https://codsen.com/images/png-codsen-ok.png" width="98" alt="ok" align="center"> <img src="https://codsen.com/images/png-codsen-1.png" width="148" alt="codsen" align="center"> <img src="https://codsen.com/images/png-codsen-star-small.png" width="32" alt="star" align="center">
diff --git a/packages/arrayiffy-if-string/package.json b/packages/arrayiffy-if-string/package.json
@@ -65,7 +65,8 @@
   "lect": {
     "licence": {
       "extras": [
-        ""
+        "",
+        "Thanks to KRyan for types https://stackoverflow.com/a/71834598/3943954"
       ]
     }
   }

diff --git a/packages/arrayiffy-if-string/src/main.ts b/packages/arrayiffy-if-string/src/main.ts
@@ -1,20 +1,16 @@
-/* eslint @typescript-eslint/explicit-module-boundary-types: 0 */
+type StringInABox<T> = T extends ""
+  ? []
+  : string extends T
+  ? [] | [string]
+  : T extends string
+  ? [T]
+  : T;
 
-// If a non-empty string is given, put it into an array.
-// If an empty string is given, return an empty array.
-// Bypass everything else.
-
-// type signature overloading
-function arrayiffy(something: string): [string];
-function arrayiffy(something: string): [];
-function arrayiffy(something: any): any {
-  if (typeof something === "string") {
-    if (something.length) {
-      return [something];
-    }
-    return [];
-  }
-  return something;
+function arrayiffy<T>(something: T): StringInABox<T>;
+function arrayiffy<T>(something: T): [] | [string] | T {
+  if (typeof something !== "string") return something;
+  if (something.length) return [something];
+  return [];
 }
 
 export { arrayiffy };
diff --git a/packages/arrayiffy-if-string/types/index.d.ts b/packages/arrayiffy-if-string/types/index.d.ts
@@ -1,4 +1,10 @@
-declare function arrayiffy(something: string): [string];
-declare function arrayiffy(something: string): [];
+declare type StringInABox<T> = T extends ""
+  ? []
+  : string extends T
+  ? [] | [string]
+  : T extends string
+  ? [T]
+  : T;
+declare function arrayiffy<T>(something: T): StringInABox<T>;
 
 export { arrayiffy };