feat: add concat

README.md

@@ -91,6 +91,7 @@ npm install string-ts
   - [uncapitalize](#uncapitalize)
 - [Strongly-typed alternatives to native runtime utilities](#strongly-typed-alternatives-to-native-runtime-utilities)
   - [chartAt](#charat)
+  - [concat](#concat)
   - [join](#join)
   - [length](#length)
   - [replace](#replace)
@@ -175,6 +176,17 @@ const result = charAt(str, 6)
 //    ^ 'w'
 ```
 
+### concat
+
+This function is a strongly-typed counterpart of `String.prototype.concat`.
+
+```ts
+import { concat } from 'string-ts'
+
+const result = concat('a', 'bc', 'def')
+//    ^ 'abcdef'
+```
+
 ### join
 
 This function is a strongly-typed counterpart of `Array.prototype.join`.
@@ -627,6 +639,7 @@ Uppercase<'hello world'> // 'HELLO WORLD'
 
 ```ts
 St.CharAt<'hello world', 6> // 'w'
+St.Concat<['a', 'bc', 'def']> // 'abcdef'
 St.Join<['hello', 'world'], '-'> // 'hello-world'
 St.Length<'hello'> // 5
 St.Replace<'hello-world', 'l', '1'> // 'he1lo-world'

src/index.ts

@@ -1,6 +1,7 @@
 // PRIMITIVES
 export type {
   CharAt,
+  Concat,
   Join,
   Length,
   Replace,
@@ -13,6 +14,7 @@ export type {
 } from './primitives'
 export {
   charAt,
+  concat,
   join,
   length,
   replace,

src/primitives.test.ts

@@ -28,6 +28,13 @@ namespace TypeTests {
     Equal<Subject.Slice<'some nice string', 5>, 'nice string'>
   >
   type test10 = Expect<Equal<Subject.Length<'some nice string'>, 16>>
+
+  type test11 = Expect<
+    Equal<
+      Subject.Concat<['a', 'bc', 'def'] | ['1', '23', '456']>,
+      'abcdef' | '123456'
+    >
+  >
 }
 
 describe('primitives', () => {

src/primitives.ts

@@ -7,7 +7,7 @@ import type { Math } from './math'
  */
 type CharAt<T extends string, index extends number> = Split<T>[index]
 /**
- * A strongly typed version of `String.prototype.charAt`.
+ * A strongly-typed version of `String.prototype.charAt`.
  * @param str the string to get the character from.
  * @param index the index of the character.
  * @returns the character in both type level and runtime.
@@ -20,6 +20,22 @@ function charAt<T extends string, I extends number>(
   return str.charAt(index)
 }
 
+/**
+ * Concatenates a tuple of strings.
+ * T: The tuple of strings to concatenate.
+ */
+type Concat<T extends string[]> = Join<T>
+
+/**
+ * A strongly-typed version of `String.prototype.concat`.
+ * @param strings the tuple of strings to concatenate.
+ * @returns the concatenated string in both type level and runtime.
+ * @example concat('a', 'bc', 'def') // 'abcdef'
+ */
+function concat<T extends string[]>(...strings: T): Concat<T> {
+  return join(strings)
+}
+
 /**
  * Joins a tuple of strings with the given delimiter.
  * T: The tuple of strings to join.
@@ -40,7 +56,7 @@ type Join<
   : ''
 
 /**
- * A strongly typed version of `Array.prototype.join`.
+ * A strongly-typed version of `Array.prototype.join`.
  * @param tuple the tuple of strings to join.
  * @param delimiter the delimiter.
  * @returns the joined string in both type level and runtime.
@@ -58,7 +74,7 @@ function join<const T extends readonly string[], D extends string = ''>(
  */
 type Length<T extends string> = Split<T>['length']
 /**
- * A strongly typed version of `String.prototype.length`.
+ * A strongly-typed version of `String.prototype.length`.
  * @param str the string to get the length from.
  * @returns the length of the string in both type level and runtime.
  * @example length('hello world') // 11
@@ -82,7 +98,7 @@ type Replace<
   : sentence
 
 /**
- * A strongly typed version of `String.prototype.replace`.
+ * A strongly-typed version of `String.prototype.replace`.
  * @param sentence the sentence to replace.
  * @param lookup the lookup string to be replaced.
  * @param replacement the replacement string.
@@ -116,7 +132,7 @@ type ReplaceAll<
   : sentence
 
 /**
- * A strongly typed version of `String.prototype.replaceAll`.
+ * A strongly-typed version of `String.prototype.replaceAll`.
  * @param sentence the sentence to replace.
  * @param lookup the lookup string to be replaced.
  * @param replacement the replacement string.
@@ -165,7 +181,7 @@ type Slice<
       >}`
   : ''
 /**
- * A strongly typed version of `String.prototype.slice`.
+ * A strongly-typed version of `String.prototype.slice`.
  * @param str the string to slice.
  * @param start the start index.
  * @param end the end index.
@@ -196,7 +212,7 @@ type Split<
   ? []
   : [T]
 /**
- * A strongly typed version of `String.prototype.split`.
+ * A strongly-typed version of `String.prototype.split`.
  * @param str the string to split.
  * @param delimiter the delimiter.
  * @returns the splitted string in both type level and runtime.
@@ -214,7 +230,7 @@ type TrimStart<T extends string> = T extends ` ${infer rest}`
   ? TrimStart<rest>
   : T
 /**
- * A strongly typed version of `String.prototype.trimStart`.
+ * A strongly-typed version of `String.prototype.trimStart`.
  * @param str the string to trim.
  * @returns the trimmed string in both type level and runtime.
  * @example trimStart(' hello world ') // 'hello world '
@@ -229,7 +245,7 @@ function trimStart<T extends string>(str: T) {
  */
 type TrimEnd<T extends string> = T extends `${infer rest} ` ? TrimEnd<rest> : T
 /**
- * A strongly typed version of `String.prototype.trimEnd`.
+ * A strongly-typed version of `String.prototype.trimEnd`.
  * @param str the string to trim.
  * @returns the trimmed string in both type level and runtime.
  * @example trimEnd(' hello world ') // ' hello world'
@@ -245,7 +261,7 @@ function trimEnd<T extends string>(str: T) {
 type Trim<T extends string> = TrimEnd<TrimStart<T>>
 
 /**
- * A strongly typed version of `String.prototype.trim`.
+ * A strongly-typed version of `String.prototype.trim`.
  * @param str the string to trim.
  * @returns the trimmed string in both type level and runtime.
  * @example trim(' hello world ') // 'hello world'
@@ -256,6 +272,7 @@ function trim<T extends string>(str: T) {
 
 export type {
   CharAt,
+  Concat,
   Join,
   Length,
   Replace,
@@ -268,6 +285,7 @@ export type {
 }
 export {
   charAt,
+  concat,
   join,
   length,
   replace,