Add string case reified types

changelog.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## [0.24.10]
+
+- Add `String.CamelCase` to convert a string to camelCase.
+- Add `String.PascalCase` to convert a string to PascalCase.
+- Add `String.SnakeCase` to convert a string to snake_case.
+- Add `String.KebabCase` to convert a string to kebab-case.
+- Add `String.ConstantCase` to convert a string to CONSTANT_CASE.
+- Reify `String.Capitalize` to a value-level function.
+- Add `String.Words` to split a string into words.
+- Add `String.IsUppercaseLetter` to check if a string is uppercase.
+- Add `String.IsLowercaseLetter` to check if a string is lowercase.
+- Add `String.IsDigit` to check if a string is a digit.
+
 ## [0.24.9]
 
 - Reify `NaturalNumber.Add` to a value-level function.

src/string/camel-case.test.ts

@@ -0,0 +1,57 @@
+import { $, Test, String } from '..'
+
+type CamelCase_Spec = [
+  /**
+   * Can convert a string to camelCase.
+   */
+  Test.Expect<$<String.CamelCase, 'hello world'>, 'helloWorld'>,
+
+  /**
+   * Can convert a string with multiple words.
+   */
+  Test.Expect<$<String.CamelCase, 'hello world 42'>, 'helloWorld42'>,
+
+  /**
+   * Can convert a string with acronyms.
+   */
+  Test.Expect<$<String.CamelCase, 'XMLHttpRequest'>, 'xmlHttpRequest'>,
+
+  /**
+   * Can convert a string with numbers.
+   */
+  Test.Expect<$<String.CamelCase, 'hello42world'>, 'hello42World'>,
+
+  /**
+   * Can convert a string with a mix of words and numbers.
+   */
+  Test.Expect<$<String.CamelCase, 'hello42world 42'>, 'hello42World42'>,
+
+  /**
+   * Can handle an empty string.
+   */
+  Test.Expect<$<String.CamelCase, ''>, ''>
+]
+
+it('should convert a string to camelCase', () => {
+  expect(String.camelCase('hello world')).toBe('helloWorld')
+})
+
+it('should convert a string with multiple words', () => {
+  expect(String.camelCase('hello world 42')).toBe('helloWorld42')
+})
+
+it('should convert a string with acronyms', () => {
+  expect(String.camelCase('XMLHttpRequest')).toBe('xmlHttpRequest')
+})
+
+it('should convert a string with numbers', () => {
+  expect(String.camelCase('hello42world')).toBe('hello42World')
+})
+
+it('should convert a string with a mix of words and numbers', () => {
+  expect(String.camelCase('hello42world 42')).toBe('hello42World42')
+})
+
+it('should handle an empty string', () => {
+  expect(String.camelCase('')).toBe('')
+})

src/string/camel-case.ts

@@ -0,0 +1,65 @@
+import { Kind, Type, String } from '..'
+
+/**
+ * `_$camelCase` is a type-level function that takes in a string `S` and returns
+ * a new string in the "camelCase" format, whereby the first letter of each word
+ * is capitalized, except for the first word. Capitalized acronyms in the input
+ * are identified.
+ *
+ * @template {string} S - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { String } from "hkt-toolbelt";
+ *
+ * type Result = String._$camelCase<'hello world'>; // 'helloWorld'
+ * ```
+ */
+export type _$camelCase<
+  S extends string,
+  WORDS extends string[] = String._$words<S>
+> = String._$fromList<{
+  [K in keyof WORDS]: K extends '0'
+    ? String._$toLower<WORDS[K]>
+    : String._$capitalize<String._$toLower<WORDS[K]>>
+}>
+
+/**
+ * `CamelCase` is a type-level function that takes in a string `S` and returns
+ * a new string in the "camelCase" format, whereby the first letter of each word
+ * is capitalized, except for the first word. Capitalized acronyms in the input
+ * are identified.
+ *
+ * @template {string} S - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { $, String } from "hkt-toolbelt";
+ *
+ * type Result = $<String.CamelCase, 'hello world'>; // 'helloWorld'
+ * ```
+ */
+export interface CamelCase extends Kind.Kind {
+  f(x: Type._$cast<this[Kind._], string>): _$camelCase<typeof x>
+}
+
+/**
+ * Given a string, return a new string in the "camelCase" format, whereby the
+ * first letter of each word is capitalized, except for the first word.
+ *
+ * @param {string} x - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { String } from "hkt-toolbelt";
+ *
+ * const result = String.camelCase('hello world')
+ * //    ^? 'helloWorld'
+ * ```
+ */
+export const camelCase = ((x: string) =>
+  String.words(x)
+    .map((word, i) =>
+      i === 0 ? word.toLowerCase() : String.capitalize(word.toLowerCase())
+    )
+    .join('')) as Kind._$reify<CamelCase>

src/string/capitalize.spec.ts → src/string/capitalize.test.ts

@@ -1,4 +1,4 @@
-import { $, Test, String } from 'hkt-toolbelt'
+import { $, Test, String } from '..'
 
 type Capitalize_Spec = [
   /**
@@ -28,3 +28,15 @@ type Capitalize_Spec = [
   // @ts-expect-error
   $<$<Capitalize, ''>, number>
 ]
+
+it('should capitalize a string', () => {
+  expect(String.capitalize('hello')).toBe('Hello')
+})
+
+it('should capitalize a string with first character already capitalized', () => {
+  expect(String.capitalize('Hello')).toBe('Hello')
+})
+
+it('should handle empty string input', () => {
+  expect(String.capitalize('')).toBe('')
+})

src/string/capitalize.ts

@@ -1,4 +1,4 @@
-import { Kind, Type } from '..'
+import _, { Kind, Type } from '..'
 
 /**
  * `String._$capitalize` is a type-level function that capitalizes the first character of a string.
@@ -27,3 +27,19 @@ interface _Capitalize extends Kind.Kind {
 }
 
 export { _Capitalize as Capitalize }
+
+/**
+ * Given a string, return a new string with the first letter capitalized.
+ *
+ * @param {string} x - The string to capitalize.
+ *
+ * @example
+ * ```ts
+ * import { String } from "hkt-toolbelt";
+ *
+ * const result = String.capitalize('hello')
+ * //    ^? 'Hello'
+ * ```
+ */
+export const capitalize = ((x: string) =>
+  x.charAt(0).toUpperCase() + x.slice(1)) as Kind._$reify<_Capitalize>

src/string/constant-case.test.ts

@@ -0,0 +1,43 @@
+import { $, Test, String } from '..'
+
+type ConstantCase_Spec = [
+  /**
+   * Can convert a string to CONSTANT_CASE.
+   */
+  Test.Expect<$<String.ConstantCase, 'hello world'>, 'HELLO_WORLD'>,
+
+  /**
+   * Can convert a string with multiple words.
+   */
+  Test.Expect<$<String.ConstantCase, 'hello world 42'>, 'HELLO_WORLD_42'>,
+
+  /**
+   * Can convert a string with acronyms.
+   */
+  Test.Expect<$<String.ConstantCase, 'XMLHttpRequest'>, 'XML_HTTP_REQUEST'>,
+
+  /**
+   * Can convert a string with numbers.
+   */
+  Test.Expect<$<String.ConstantCase, 'hello42world'>, 'HELLO_42_WORLD'>
+]
+
+it('should convert a string to CONSTANT_CASE', () => {
+  expect(String.constantCase('hello world')).toBe('HELLO_WORLD')
+})
+
+it('should convert a string with multiple words', () => {
+  expect(String.constantCase('hello world 42')).toBe('HELLO_WORLD_42')
+})
+
+it('should convert a string with acronyms', () => {
+  expect(String.constantCase('XMLHttpRequest')).toBe('XML_HTTP_REQUEST')
+})
+
+it('should convert a string with numbers', () => {
+  expect(String.constantCase('hello42world')).toBe('HELLO_42_WORLD')
+})
+
+it('should handle an empty string', () => {
+  expect(String.constantCase('')).toBe('')
+})

src/string/constant-case.ts

@@ -0,0 +1,62 @@
+import { Kind, Type, String as String_ } from '..'
+
+/**
+ * `_$constantCase` is a type-level function that takes in a string `S` and returns
+ * a new string in the "CONSTANT_CASE" format, whereby each word is uppercased
+ * and separated by underscores.
+ *
+ * @template {string} S - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { String } from "hkt-toolbelt";
+ *
+ * type Result = String._$constantCase<'hello world'>; // 'HELLO_WORLD'
+ * ```
+ */
+export type _$constantCase<
+  S extends string,
+  WORDS extends string[] = String_._$words<S>
+> = String_._$join<
+  {
+    [K in keyof WORDS]: String_._$toUpper<WORDS[K]>
+  },
+  '_'
+>
+
+/**
+ * `ConstantCase` is a type-level function that takes in a string `S` and returns
+ * a new string in the "CONSTANT_CASE" format, whereby each word is uppercased
+ * and separated by underscores.
+ *
+ * @template {string} S - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { $, String } from "hkt-toolbelt";
+ *
+ * type Result = $<String.ConstantCase, 'hello world'>; // 'HELLO_WORLD'
+ * ```
+ */
+export interface ConstantCase extends Kind.Kind {
+  f(x: Type._$cast<this[Kind._], string>): _$constantCase<typeof x>
+}
+
+/**
+ * Given a string, return a new string in the "CONSTANT_CASE" format, whereby
+ * each word is uppercased and separated by underscores.
+ *
+ * @param {string} x - The string to convert.
+ *
+ * @example
+ * ```ts
+ * import { String } from "hkt-toolbelt";
+ *
+ * const result = String.constantCase('hello world')
+ * //    ^? 'HELLO_WORLD'
+ * ```
+ */
+export const constantCase = ((x: string) =>
+  String_.words(x)
+    .map((word) => word.toUpperCase())
+    .join('_')) as Kind._$reify<ConstantCase>

src/string/index.ts

@@ -1,28 +1,37 @@
 export * from './append'
+export * from './camel-case'
 export * from './capitalize'
+export * from './constant-case'
 export * from './ends-with'
 export * from './entries'
 export * from './first'
 export * from './from-char-code'
 export * from './from-list'
 export * from './includes'
 export * from './init'
+export * from './is-digit'
 export * from './is-letter'
+export * from './is-lowercase-letter'
 export * from './is-string'
 export * from './is-template'
+export * from './is-uppercase-letter'
 export * from './join'
+export * from './kebab-case'
 export * from './last'
 export * from './length'
 export * from './pad-end'
 export * from './pad-start'
+export * from './pascal-case'
 export * from './prepend'
 export * from './replace'
 export * from './reverse'
 export * from './slice'
+export * from './snake-case'
 export * from './split'
 export * from './starts-with'
 export * from './tail'
 export * from './to-char-code'
 export * from './to-list'
 export * from './to-lower'
 export * from './to-upper'
+export * from './words'

src/string/is-digit.test.ts

@@ -0,0 +1,45 @@
+import { $, String, Test } from '..'
+
+type IsDigit_Spec = [
+  /**
+   * Can check if a string is a digit.
+   */
+  Test.Expect<$<String.IsDigit, '0'>, true>,
+
+  /**
+   * Can check if a string is a digit
+   */
+  Test.Expect<$<String.IsDigit, '9'>, true>,
+
+  /**
+   * Can check if a string is not a digit.
+   */
+  Test.Expect<$<String.IsDigit, 'a'>, false>,
+
+  /**
+   * An empty string is not a digit.
+   */
+  Test.Expect<$<String.IsDigit, ''>, false>,
+
+  /**
+   * A general string is not a digit.
+   */
+  Test.Expect<$<String.IsDigit, 'foo'>, false>,
+
+  /**
+   * A template literal string is not a digit.
+   */
+  Test.Expect<$<String.IsDigit, `0${string}1`>, false>
+]
+
+it('should check if a string is a digit', () => {
+  expect(String.isDigit('0')).toBe(true)
+})
+
+it('returns false for an empty string', () => {
+  expect(String.isDigit('')).toBe(false)
+})
+
+it('returns false for a general string', () => {
+  expect(String.isDigit('000')).toBe(false)
+})