feat: add concat

gustavoguichard · Oct 4, 2023 · 4fa1cf2 · 4fa1cf2
1 parent 2cf8123
commit 4fa1cf2
Show file tree

Hide file tree

Showing 2 changed files with 25 additions and 1 deletion.
diff --git a/src/primitives.test.ts b/src/primitives.test.ts
@@ -24,6 +24,13 @@ namespace TypeTests {
     Equal<Subject.Split<'some nice string', ' '>, ['some', 'nice', 'string']>
   >
   type test8 = Expect<Equal<Subject.CharAt<'some nice string', 5>, 'n'>>
+
+  type test9 = Expect<
+    Equal<
+      Subject.Concat<['a', 'bc', 'def'] | ['1', '23', '456']>,
+      'abcdef' | '123456'
+    >
+  >
 }
 
 describe('primitives', () => {

diff --git a/src/primitives.ts b/src/primitives.ts
@@ -18,6 +18,12 @@ function charAt<T extends string, I extends number>(
   return str.charAt(index)
 }
 
+type Concat<T extends string[]> = Join<T, ''>
+
+function concat<T extends string[]>(...strings: T): Concat<T> {
+  return strings.join('') as Concat<T>
+}
+
 /**
  * Joins a tuple of strings with the given delimiter.
  * T: The tuple of strings to join.
@@ -193,6 +199,7 @@ function trim<T extends string>(str: T) {
 
 export type {
   CharAt,
+  Concat,
   Join,
   Replace,
   ReplaceAll,
@@ -201,4 +208,14 @@ export type {
   TrimEnd,
   Trim,
 }
-export { charAt, join, replace, replaceAll, split, trim, trimStart, trimEnd }
+export {
+  charAt,
+  concat,
+  join,
+  replace,
+  replaceAll,
+  split,
+  trim,
+  trimStart,
+  trimEnd,
+}