Add more string utils

Author: maxfriedmann

lib/modules/string/string.utils.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, test } from "vitest";
-import { upperCaseFirst } from "./string.utils";
+import {
+  camelCaseToSnakeCase,
+  lowerCaseFirst,
+  snakeCaseToCamelCase,
+  upperCaseFirst,
+} from "./string.utils";
 
 describe("upperCaseFirst", () => {
   test("should return an empty string when input is an empty string", () => {
@@ -27,3 +32,64 @@ describe("upperCaseFirst", () => {
     expect(upperCaseFirst(" hello")).toBe(" hello");
   });
 });
+
+describe("lowerCaseFirst", () => {
+  test("should return an empty string when input is an empty string", () => {
+    expect(lowerCaseFirst("")).toBe("");
+  });
+
+  test("should lowercase the first letter of a single character string", () => {
+    expect(lowerCaseFirst("A")).toBe("a");
+  });
+
+  test("should lowercase the first letter of a multiple character string", () => {
+    expect(lowerCaseFirst("Hello")).toBe("hello");
+  });
+
+  test("should return the same string if the first character is already lowercase", () => {
+    expect(lowerCaseFirst("hello")).toBe("hello");
+  });
+
+  test("should handle strings with special characters correctly", () => {
+    expect(lowerCaseFirst("!Hello")).toBe("!Hello");
+    expect(lowerCaseFirst("123Hello")).toBe("123Hello");
+  });
+
+  test("should handle strings with leading whitespace correctly", () => {
+    expect(lowerCaseFirst(" Hello")).toBe(" Hello");
+  });
+});
+
+describe("camelCaseToSnakeCase", () => {
+  test("should convert camelCase to snake_case", () => {
+    expect(camelCaseToSnakeCase("helloWorld")).toBe("hello_world");
+  });
+
+  test("should handle strings with special characters correctly", () => {
+    expect(camelCaseToSnakeCase("helloWorld!")).toBe("hello_world!");
+    expect(camelCaseToSnakeCase("helloWorld123")).toBe("hello_world123");
+  });
+
+  test("should handle strings with leading whitespace correctly", () => {
+    expect(camelCaseToSnakeCase(" helloWorld")).toBe(" hello_world");
+  });
+});
+
+describe("snakeCaseToCamelCase", () => {
+  test("should convert snake_case to camelCase", () => {
+    expect(snakeCaseToCamelCase("hello_world")).toBe("HelloWorld");
+  });
+
+  test("should convert snake_case to lowerCamelCase", () => {
+    expect(snakeCaseToCamelCase("hello_world", true)).toBe("helloWorld");
+  });
+
+  test("should handle strings with special characters correctly", () => {
+    expect(snakeCaseToCamelCase("hello_world!")).toBe("HelloWorld!");
+    expect(snakeCaseToCamelCase("hello_world123")).toBe("HelloWorld123");
+  });
+
+  test("should handle strings with leading whitespace correctly", () => {
+    expect(snakeCaseToCamelCase(" hello_world")).toBe(" helloWorld");
+  });
+});

lib/modules/string/string.utils.ts

@@ -1,10 +1,40 @@
-/**
- * Capitalize the first letter of a string
- *
- * @param str The input string
- * @returns The string with the first letter capitalized
- */
+/** Capitalize the first letter of a string */
 export function upperCaseFirst(str: string): string {
   if (!str) return str;
   return str.charAt(0).toUpperCase() + str.slice(1);
 }
+
+/** Lowercase the first letter of a string */
+export function lowerCaseFirst(str: string): string {
+  if (typeof str !== "string") return str;
+  return str.charAt(0).toLowerCase() + str.slice(1);
+}
+
+/** Converts "HelloWorld" to "hello_world" */
+export function camelCaseToSnakeCase(str: string): string {
+  return lowerCaseFirst(str).replace(
+    /[A-Z]/g,
+    (letter) => `_${letter.toLowerCase()}`
+  );
+}
+
+/** Converts "hello-world" or "hello_world" to "HelloWorld" */
+export function snakeCaseToCamelCase(
+  str: string,
+  lowerCamelCase = false
+): string {
+  const camelCase = str.replace(/([-_][a-zA-Z])/g, (group) =>
+    group.toUpperCase().replace("-", "").replace("_", "")
+  );
+  if (lowerCamelCase) return lowerCaseFirst(camelCase);
+  return upperCaseFirst(camelCase);
+}
+
+/** Returns a string based on the current (or given) timestamp */
+export function getTimeAsCharacters(timestamp = Date.now()): string {
+  return timestamp
+    .toString()
+    .split("")
+    .map((n) => (Number(n) + 10).toString(36))
+    .join("");
+}