fix: narrow types for SplitByCase

unjs · Nov 20, 2024 · 80248aa · 80248aa
1 parent 7d7883d
commit 80248aa
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Showing 3 changed files with 15 additions and 12 deletions.
diff --git a/src/types.ts b/src/types.ts
@@ -21,21 +21,18 @@ type CapitalizedWords<
   Accumulator extends string = "",
 > = T extends readonly []
   ? Accumulator
-  : T extends readonly [infer F extends string]
+  : T extends readonly [infer F extends string, ...infer R extends string[]]
     ? CapitalizedWords<
-        [],
+        R,
         Joiner,
         Normalize,
-        `${Accumulator}${Capitalize<Normalize extends true ? Lowercase<F> : F>}`
+        `${Accumulator}${Capitalize<Normalize extends true ? Lowercase<F> : F>}${[
+          LastOfArray<R>,
+        ] extends [never]
+          ? ""
+          : Joiner}`
       >
-    : T extends readonly [infer F extends string, ...infer R extends string[]]
-      ? CapitalizedWords<
-          R,
-          Joiner,
-          Normalize,
-          `${Accumulator}${Capitalize<Normalize extends true ? Lowercase<F> : F>}${Joiner}`
-        >
-      : Accumulator;
+    : Accumulator;
 
 type JoinLowercaseWords<
   T extends readonly string[],
@@ -99,7 +96,9 @@ export type SplitByCase<
   ? string[]
   : T extends `${infer F}${infer R}`
     ? [LastOfArray<Accumulator>] extends [never]
-      ? SplitByCase<R, Separator, [F]>
+      ? F extends Separator | Whitespace
+        ? SplitByCase<R, Separator, []>
+        : SplitByCase<R, Separator, [F]>
       : LastOfArray<Accumulator> extends string
         ? R extends ""
           ? SplitByCase<

diff --git a/test/scule.test.ts b/test/scule.test.ts
@@ -25,6 +25,8 @@ describe("splitByCase", () => {
     ["foo123-bar", ["foo123", "bar"]],
     ["FOOBar", ["FOO", "Bar"]],
     ["ALink", ["A", "Link"]],
+    ["-FooBar", ["", "Foo", "Bar"]],
+    [" FooBar", ["", "Foo", "Bar"]],
     // with custom splitters
     [
       "foo\\Bar.fuzz-FIZz",

diff --git a/test/types.test-d.ts b/test/types.test-d.ts
@@ -24,6 +24,8 @@ describe("SplitByCase", () => {
     assertType<SplitByCase<"ALink">>(["A", "Link"]);
     assertType<SplitByCase<"FOO_BAR">>(["FOO", "BAR"]);
     assertType<SplitByCase<"Foo Bar Baz">>(["Foo", "Bar", "Baz"]);
+    assertType<SplitByCase<"-Bar Baz">>(["Bar", "Baz"]);
+    assertType<SplitByCase<" Bar Baz">>(["Bar", "Baz"]);
   });
 
   test("custom splitters", () => {