diff --git a/src/utils/string-utils.ts b/src/utils/string-utils.ts
new file mode 100644
index 0000000..d98c103
--- /dev/null
+++ b/src/utils/string-utils.ts
@@ -0,0 +1,465 @@
+import { createHash, randomBytes } from "node:crypto";
+import { IGNORE_CASE_COMPARER, ORDINAL_COMPARER } from "@/utils/comparison";
+
+/**
+ * Returns the input value converted to a string.
+ *
+ * If the input value is already a string, it is returned as-is.
+ * Otherwise, the output of `String()` is returned.
+ *
+ * @param s - The input value to convert to a string.
+ *
+ * @returns The input value as a string.
+ */
+export function asString(s: unknown): string {
+    return typeof s === "string" ? s : String(s);
+}
+
+/**
+ * A regular expression that matches a string consisting of a single letter character.
+ */
+export const IS_LETTER_REGEX = /^\p{L}$/u;
+
+/**
+ * Checks if the provided string is a single letter.
+ *
+ * @param s - The string to check.
+ *
+ * @returns `true` if the string is a single letter; otherwise, `false`.
+ */
+export function isLetter(s: string): boolean {
+    return s?.length === 1 && IS_LETTER_REGEX.test(s);
+}
+
+/**
+ * A regular expression that matches a string consisting of a single digit character.
+ */
+export const IS_DIGIT_REGEX = /^\d$/;
+
+/**
+ * Checks if the provided string is a single digit.
+ *
+ * @param s - The string to check.
+ *
+ * @returns `true` if the string is a single digit; otherwise, `false`.
+ */
+export function isDigit(s: string): boolean {
+    return s?.length === 1 && s >= "0" && s <= "9";
+}
+
+/**
+ * A regular expression that matches a string consisting of a single letter or digit character.
+ */
+export const IS_LETTER_OR_DIGIT_REGEX = /^(?:\p{L}|\d)$/u;
+
+/**
+ * Checks if the provided string is a single letter or digit.
+ *
+ * @param s - The string to check.
+ *
+ * @returns `true` if the string is a single letter or digit; otherwise, `false`.
+ */
+export function isLetterOrDigit(s: string): boolean {
+    return s?.length === 1 && IS_LETTER_OR_DIGIT_REGEX.test(s);
+}
+
+/**
+ * A regular expression that matches strings containing only uppercase characters
+ * and not containing any lowercase Unicode characters.
+ */
+export const IS_UPPER_CASE_REGEX = /^[^\p{Ll}]*$/u;
+
+/**
+ * Checks if a string contains only uppercase characters.
+ *
+ * @param s - The string to check.
+ *
+ * @returns `true` if the input string contains only uppercase characters; otherwise, `false`.
+ */
+export function isUpperCase(s: string): boolean {
+    return IS_UPPER_CASE_REGEX.test(s);
+}
+
+/**
+ * A regular expression that matches strings containing only lowercase characters
+ * and not containing any uppercase Unicode characters.
+ */
+export const IS_LOWER_CASE_REGEX = /^[^\p{Lu}]*$/u;
+
+/**
+ * Checks if a string contains only lowercase characters.
+ *
+ * @param s - The string to check.
+ *
+ * @returns `true` if the input string contains only lowercase characters; otherwise, `false`.
+ */
+export function isLowerCase(s: string): boolean {
+    return IS_LOWER_CASE_REGEX.test(s);
+}
+
+/**
+ * Checks if a given string represents a valid number.
+ *
+ * @param s - The string to be checked.
+ *
+ * @returns `true` if the string represents a valid number; otherwise, `false`.
+ */
+export function isNumberString(s: string): boolean {
+    return String(+s) === s;
+}
+
+/**
+ * Checks if a given string represents a valid integer number.
+ *
+ * @param s - The string to be checked.
+ *
+ * @returns `true` if the string represents a valid integer number; otherwise, `false`.
+ */
+export function isIntegerString(s: string): boolean {
+    return String(parseInt(s)) === s;
+}
+
+/**
+ * Options for comparing strings.
+ */
+export interface StringComparisonOptions {
+    /**
+     * Indicates whether the comparison should ignore the case of the strings being compared.
+     * If `ignoreCase` is `true`, the comparison will use lexicographical sort rules while
+     * ignoring the case of the strings being compared.
+     */
+    ignoreCase?: boolean;
+}
+
+/**
+ * Compares two strings lexicographically and returns a value indicating whether one string is less than, equal to, or greater than the other.
+ *
+ * @param left - The first string to compare.
+ * @param right - The second string to compare.
+ * @param options - Options for comparing strings.
+ *
+ * @returns A value indicating the comparison result:
+ *
+ *  - A value less than 0 indicates that `left` is less than `right`.
+ *  - 0 indicates that `left` is equal to `right`.
+ *  - A value greater than 0 indicates that `left` is greater than `right`.
+ */
+export function stringCompare(left: string, right: string, options?: StringComparisonOptions): number {
+    const comparer = options?.ignoreCase ? IGNORE_CASE_COMPARER : ORDINAL_COMPARER;
+    return comparer.compare(left, right);
+}
+
+/**
+ * Compares two strings.
+ *
+ * @param left - The first string to compare.
+ * @param right - The second string to compare.
+ * @param options - Options for comparing strings.
+ *
+ * @returns `true` if the strings are equal; otherwise, `false`.
+ */
+export function stringEquals(left: string, right: string, options?: StringComparisonOptions): boolean {
+    return stringCompare(left, right, options) === 0;
+}
+
+/**
+ * Capitalizes the first letter of a string.
+ *
+ * @param s - The string to capitalize.
+ *
+ * @returns The capitalized string.
+ */
+export function capitalize(s: string): string {
+    return s.charAt(0).toUpperCase() + s.slice(1);
+}
+
+/**
+ * Converts the first character of a string to lowercase.
+ *
+ * @param s - The input string.
+ *
+ * @returns The input string with the first character converted to lowercase.
+ */
+export function uncapitalize(s: string): string {
+    return s.charAt(0).toLowerCase() + s.slice(1);
+}
+
+/**
+ * Converts a string to PascalCase.
+ *
+ * This function can handle input strings in the following formats:
+ * - PascalCase
+ * - camelCase
+ * - kebab-case
+ * - snake_case
+ * - SCREAMING_SNAKE_CASE
+ *
+ * @param s - The input string to be converted to PascalCase.
+ *
+ * @returns The input string converted to PascalCase.
+ */
+export function toPascalCase(s: string): string {
+    // Convert input to lowercase if the entire string is in uppercase (SCREAMING_SNAKE_CASE)
+    if (isUpperCase(s)) {
+        s = s.toLowerCase();
+    }
+
+    return s
+        // Replace any character following a non-word character (such as - or _) with its uppercase counterpart
+        .replace(/(?:^|[\s_-])(\w)/g, (_, char) => char.toUpperCase())
+        // Remove any non-word characters (such as - or _) from the result
+        .replace(/[\s_-]/g, "");
+}
+
+/**
+ * Specifies how the results should be transformed when splitting a string into substrings.
+ */
+export interface StringSplitOptions {
+    /**
+     * Remove empty (zero-length) substrings from the result.
+     */
+    removeEmptyEntries?: boolean;
+
+    /**
+     * Trim whitespace from each substring in the result.
+     */
+    trimEntries?: boolean;
+}
+
+/**
+ * Splits a string into an array of substrings based on a separator.
+ *
+ * @param s - The input string to split.
+ * @param separator - The separator to split the string by.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+export function split(s: string, separator: string, options?: StringSplitOptions): string[];
+
+/**
+ * Splits a string into an array of substrings based on the given separators.
+ *
+ * @param s - The input string to split.
+ * @param separators - The array of separators to split the string by.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+export function split(s: string, separators: readonly string[], options?: StringSplitOptions): string[];
+
+/**
+ * Returns an array of substrings that were delimited by strings in the original input that
+ * match against the `splitter` regular expression.
+ *
+ * @param s - The input string to split.
+ * @param splitter - The regular expression to split the string by.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+export function split(s: string, splitter: RegExp, options?: StringSplitOptions): string[];
+
+/**
+ * Splits a string into an array of substrings based on a separator.
+ *
+ * @param s - The string to split.
+ * @param separator - The separator to split the string by. Can be a string, a regular expression, or an array of strings.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+export function split(s: string, separator: string | RegExp | readonly string[], options?: StringSplitOptions): string[] {
+    if (!s) {
+        return [];
+    }
+
+    if (Array.isArray(separator)) {
+        return splitByArrayOfStrings(s, separator, options);
+    }
+    return splitByStringOrRegex(s, separator as string | RegExp, options);
+}
+
+/**
+ * Split a string into substrings using the specified separator and return them as an array.
+ *
+ * @param s - The string to split.
+ * @param separator - The separator to split the string by. Can be a string, or a regular expression.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+function splitByStringOrRegex(s: string, separator: string | RegExp, options?: StringSplitOptions): string[] {
+    const trimEntries = options?.trimEntries ?? false;
+    const removeEmptyEntries = options?.removeEmptyEntries ?? false;
+    const parts = s.split(separator);
+
+    if (trimEntries) {
+        for (let i = 0; i < parts.length; ++i) {
+            parts[i] = parts[i].trim();
+        }
+    }
+    return removeEmptyEntries ? parts.filter(x => x) : parts;
+}
+
+/**
+ * Splits a string into an array of substrings based on the given separators.
+ *
+ * @param s - The input string to split.
+ * @param separators - The array of separators to split the string by.
+ * @param options - Options for splitting the string.
+ *
+ * @returns An array of substrings from the original string.
+ */
+function splitByArrayOfStrings(s: string, separators: readonly string[], options?: StringSplitOptions): string[] {
+    const trimEntries = options?.trimEntries ?? false;
+    const removeEmptyEntries = options?.removeEmptyEntries ?? false;
+    const splitted = [];
+
+    let previousIndex = -1;
+    for (let i = 0; i < s.length; ++i) {
+        if (!separators.includes(s.charAt(i))) {
+            continue;
+        }
+
+        let part = s.substring(previousIndex + 1, i);
+        previousIndex = i;
+
+        if (trimEntries) {
+            part = part.trim();
+        }
+
+        if (part || !removeEmptyEntries) {
+            splitted.push(part);
+        }
+    }
+
+    let lastPart = s.substring(previousIndex + 1);
+
+    if (trimEntries) {
+        lastPart = lastPart.trim();
+    }
+
+    if (lastPart || !removeEmptyEntries) {
+        splitted.push(lastPart);
+    }
+
+    return splitted;
+}
+
+/**
+ * Represents options for splitting a string into multiple lines.
+ */
+export interface StringSplitLineOptions {
+    /**
+     * The maximum length of each line.
+     */
+    maxLength?: number;
+}
+
+/**
+ * Splits a string into an array of lines.
+ *
+ * @param text - The input string to split.
+ * @param options - An optional object that specifies the options for splitting the string, including the maximum line length.
+ *
+ * @returns An array of strings, where each string represents a line from the input string. If the `maxLength` option is specified, the lines will be truncated at the specified length.
+ */
+export function splitLines(text: string, options?: StringSplitLineOptions): string[] {
+    const maxLength = options?.maxLength || 0;
+
+    const lines = text.split(/\r?\n/);
+    if (maxLength <= 0) {
+        return lines;
+    }
+
+    const shortenedLines = lines.flatMap(line => {
+        if (line.length <= maxLength) {
+            return line;
+        }
+
+        const words = line.split(" ");
+        const linesFromCurrentLine = [] as string[];
+        let currentLine = "";
+
+        for (const word of words) {
+            if (currentLine.length + word.length <= maxLength) {
+                currentLine += (currentLine ? " " : "") + word;
+            } else {
+                linesFromCurrentLine.push(currentLine);
+                currentLine = word;
+            }
+        }
+
+        linesFromCurrentLine.push(currentLine);
+        return linesFromCurrentLine;
+    });
+
+    return shortenedLines;
+}
+
+/**
+ * Represents options for padding a string with spaces or a specific fill character.
+ */
+export interface StringPadOptions {
+    /**
+     * The fill character to use when padding the string. If not specified, spaces will be used.
+     */
+    fillString?: string;
+
+    /**
+     * The alignment of the padded string within the specified maximum length.
+     */
+    align?: "left" | "center" | "right";
+}
+
+/**
+ * Pads a string with spaces or a specific fill character to the specified maximum length.
+ *
+ * @param s - The input string to pad.
+ * @param maxLength - The maximum length of the padded string.
+ * @param options - An optional object that specifies the options for padding the string.
+ *
+ * @returns A string that represents the padded input string according to the specified options.
+ */
+export function pad(s: string, maxLength: number, options?: StringPadOptions): string {
+    s ||= "";
+
+    switch (options?.align) {
+        case "left":
+            return s.padEnd(maxLength, options?.fillString);
+        case "right":
+            return s.padStart(maxLength, options?.fillString);
+        default:
+            const availableLength = maxLength - s.length;
+            if (availableLength <= 0) {
+                return s;
+            }
+            const padStartLength = (availableLength >> 1) + s.length;
+            return s.padStart(padStartLength, options?.fillString).padEnd(maxLength, options?.fillString);
+    }
+}
+
+/**
+ * Generates a secure random string of a specified length.
+ *
+ * @param length - The desired length of the generated string.
+ *
+ * @returns The secure random string in hexadecimal format.
+ */
+export function generateSecureRandomString(length: number): string {
+    const bytes = randomBytes(Math.ceil(length / 2));
+    return bytes.toString("hex").slice(0, length);
+}
+
+/**
+ * Hashes a string using the specified algorithm.
+ *
+ * @param input - The string to be hashed.
+ * @param algorithm - The hashing algorithm to use (default: "sha256").
+ *
+ * @returns The hashed string in hexadecimal format.
+ */
+export function hashString(input: string, algorithm: string = "sha256"): string {
+    return createHash(algorithm).update(input).digest("hex");
+}
diff --git a/tests/unit/utils/string-utils.spec.ts b/tests/unit/utils/string-utils.spec.ts
new file mode 100644
index 0000000..b3e6f22
--- /dev/null
+++ b/tests/unit/utils/string-utils.spec.ts
@@ -0,0 +1,446 @@
+import {
+    asString,
+    isLetter,
+    IS_LETTER_REGEX,
+    isDigit,
+    IS_DIGIT_REGEX,
+    isLetterOrDigit,
+    IS_LETTER_OR_DIGIT_REGEX,
+    isUpperCase,
+    IS_UPPER_CASE_REGEX,
+    isLowerCase,
+    IS_LOWER_CASE_REGEX,
+    isNumberString,
+    isIntegerString,
+    stringCompare,
+    stringEquals,
+    capitalize,
+    uncapitalize,
+    toPascalCase,
+    split,
+    splitLines,
+    pad,
+    generateSecureRandomString,
+    hashString,
+} from "@/utils/string-utils";
+import { createHash } from "node:crypto";
+
+describe("asString", () => {
+    test("returns string as is", () => {
+        expect(asString("test")).toBe("test");
+    });
+
+    test("converts non-string value to string", () => {
+        expect(asString(123)).toBe("123");
+    });
+
+    test("converts undefined value to string", () => {
+        expect(asString(undefined)).toBe("undefined");
+    });
+
+    test("converts null value to string", () => {
+        expect(asString(null)).toBe("null");
+    });
+});
+
+describe("isLetter", () => {
+    test("returns true for a single letter", () => {
+        expect(isLetter("a")).toBe(true);
+    });
+
+    test("returns false for a string of multiple letters", () => {
+        expect(isLetter("abc")).toBe(false);
+    });
+
+    test("returns false for a digit", () => {
+        expect(isLetter("1")).toBe(false);
+    });
+
+    test("returns false for an empty string", () => {
+        expect(isLetter("")).toBe(false);
+    });
+});
+
+describe("IS_LETTER_REGEX", () => {
+    test("matches a single letter", () => {
+        expect(IS_LETTER_REGEX.test("a")).toBe(true);
+    });
+
+    test("does not match a string of multiple letters", () => {
+        expect(IS_LETTER_REGEX.test("abc")).toBe(false);
+    });
+
+    test("does not match a digit", () => {
+        expect(IS_LETTER_REGEX.test("1")).toBe(false);
+    });
+
+    test("does not match an empty string", () => {
+        expect(IS_LETTER_REGEX.test("")).toBe(false);
+    });
+});
+
+describe("isDigit", () => {
+    test("returns true for a single digit", () => {
+        expect(isDigit("1")).toBe(true);
+    });
+
+    test("returns false for a string of multiple digits", () => {
+        expect(isDigit("123")).toBe(false);
+    });
+
+    test("returns false for a letter", () => {
+        expect(isDigit("a")).toBe(false);
+    });
+
+    test("returns false for an empty string", () => {
+        expect(isDigit("")).toBe(false);
+    });
+});
+
+describe("IS_DIGIT_REGEX", () => {
+    test("matches a single digit", () => {
+        expect(IS_DIGIT_REGEX.test("1")).toBe(true);
+    });
+
+    test("does not match a string of multiple digits", () => {
+        expect(IS_DIGIT_REGEX.test("123")).toBe(false);
+    });
+
+    test("does not match a letter", () => {
+        expect(IS_DIGIT_REGEX.test("a")).toBe(false);
+    });
+
+    test("does not match an empty string", () => {
+        expect(IS_DIGIT_REGEX.test("")).toBe(false);
+    });
+});
+
+describe("isLetterOrDigit", () => {
+    test("returns true for a single letter", () => {
+        expect(isLetterOrDigit("a")).toBe(true);
+    });
+
+    test("returns true for a single digit", () => {
+        expect(isLetterOrDigit("1")).toBe(true);
+    });
+
+    test("returns false for a string of multiple letters or digits", () => {
+        expect(isLetterOrDigit("123")).toBe(false);
+        expect(isLetterOrDigit("abc")).toBe(false);
+    });
+
+    test("returns false for a non-letter and non-digit character", () => {
+        expect(isLetterOrDigit("@")).toBe(false);
+    });
+
+    test("returns false for an empty string", () => {
+        expect(isLetterOrDigit("")).toBe(false);
+    });
+});
+
+describe("IS_LETTER_OR_DIGIT_REGEX", () => {
+    test("matches a single letter", () => {
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("a")).toBe(true);
+    });
+
+    test("matches a single digit", () => {
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("1")).toBe(true);
+    });
+
+    test("does not match a string of multiple letters or digits", () => {
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("123")).toBe(false);
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("abc")).toBe(false);
+    });
+
+    test("does not match a non-letter and non-digit character", () => {
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("@")).toBe(false);
+    });
+
+    test("does not match an empty string", () => {
+        expect(IS_LETTER_OR_DIGIT_REGEX.test("")).toBe(false);
+    });
+});
+
+describe("isUpperCase", () => {
+    test("returns true for a string of uppercase letters", () => {
+        expect(isUpperCase("ABC")).toBe(true);
+    });
+
+    test("returns true for a string of uppercase letters and non-letter characters", () => {
+        expect(isUpperCase("HELLO WORLD! 42 IS THE ANSWER.")).toBe(true);
+    });
+
+    test("returns true for an empty string", () => {
+        expect(isUpperCase("")).toBe(true);
+    });
+
+    test("returns false for a string of lowercase letters", () => {
+        expect(isUpperCase("abc")).toBe(false);
+    });
+
+    test("returns false for a mixed-case string", () => {
+        expect(isUpperCase("AbC")).toBe(false);
+    });
+});
+
+describe("IS_UPPER_CASE_REGEX", () => {
+    test("matches a string of uppercase letters", () => {
+        expect(IS_UPPER_CASE_REGEX.test("ABC")).toBe(true);
+    });
+
+    test("matches a string of uppercase letters and non-letter characters", () => {
+        expect(IS_UPPER_CASE_REGEX.test("HELLO WORLD! 42 IS THE ANSWER.")).toBe(true);
+    });
+
+    test("matches an empty string", () => {
+        expect(IS_UPPER_CASE_REGEX.test("")).toBe(true);
+    });
+
+    test("does not match a string of lowercase letters", () => {
+        expect(IS_UPPER_CASE_REGEX.test("abc")).toBe(false);
+    });
+
+    test("does not match a mixed-case string", () => {
+        expect(IS_UPPER_CASE_REGEX.test("AbC")).toBe(false);
+    });
+});
+
+describe("isLowerCase", () => {
+    test("returns true for a string of lowercase letters", () => {
+        expect(isLowerCase("abc")).toBe(true);
+    });
+
+    test("returns true for a string of lowercase letters and non-letter characters", () => {
+        expect(isLowerCase("hello world! 42 is the answer.")).toBe(true);
+    });
+
+    test("returns true for an empty string", () => {
+        expect(isLowerCase("")).toBe(true);
+    });
+
+    test("returns false for a string of uppercase letters", () => {
+        expect(isLowerCase("ABC")).toBe(false);
+    });
+
+    test("returns false for a mixed-case string", () => {
+        expect(isLowerCase("AbC")).toBe(false);
+    });
+});
+
+describe("IS_LOWER_CASE_REGEX", () => {
+    test("matches a string of lowercase letters", () => {
+        expect(IS_LOWER_CASE_REGEX.test("abc")).toBe(true);
+    });
+
+    test("matches a string of lowercase letters and non-letter characters", () => {
+        expect(IS_LOWER_CASE_REGEX.test("hello world! 42 is the answer.")).toBe(true);
+    });
+
+    test("matches an empty string", () => {
+        expect(IS_LOWER_CASE_REGEX.test("")).toBe(true);
+    });
+
+    test("does not match a string of uppercase letters", () => {
+        expect(IS_LOWER_CASE_REGEX.test("ABC")).toBe(false);
+    });
+
+    test("does not match a mixed-case string", () => {
+        expect(IS_LOWER_CASE_REGEX.test("AbC")).toBe(false);
+    });
+});
+
+describe("isNumberString", () => {
+    test("returns true for a valid number string", () => {
+        expect(isNumberString("123")).toBe(true);
+        expect(isNumberString("0.5")).toBe(true);
+    });
+
+    test("returns false for a non-number string", () => {
+        expect(isNumberString("abc")).toBe(false);
+    });
+});
+
+describe("isIntegerString", () => {
+    test("returns true for a valid integer string", () => {
+        expect(isIntegerString("123")).toBe(true);
+    });
+
+    test("returns false for a non-number string", () => {
+        expect(isIntegerString("abc")).toBe(false);
+    });
+
+    test("returns false for a non-integer string", () => {
+        expect(isIntegerString("0.5")).toBe(false);
+    });
+});
+
+describe("stringCompare", () => {
+    test("compares two strings", () => {
+        expect(stringCompare("abc", "def")).toBeLessThan(0);
+        expect(stringCompare("def", "abc")).toBeGreaterThan(0);
+        expect(stringCompare("abc", "abc")).toBe(0);
+    });
+
+    test("compares two strings ignoring case", () => {
+        expect(stringCompare("abc", "DEF", { ignoreCase: true })).toBeLessThan(0);
+        expect(stringCompare("ABC", "def", { ignoreCase: true })).toBeLessThan(0);
+        expect(stringCompare("DEF", "abc", { ignoreCase: true })).toBeGreaterThan(0);
+        expect(stringCompare("def", "ABC", { ignoreCase: true })).toBeGreaterThan(0);
+        expect(stringCompare("abc", "ABC", { ignoreCase: true })).toBe(0);
+        expect(stringCompare("ABC", "abc", { ignoreCase: true })).toBe(0);
+    });
+});
+
+describe("stringEquals", () => {
+    test("compares two strings for equality", () => {
+        expect(stringEquals("abc", "abc")).toBe(true);
+        expect(stringEquals("abc", "def")).toBe(false);
+    });
+
+    test("compares two strings for equality ignoring case", () => {
+        expect(stringEquals("abc", "ABC", { ignoreCase: true })).toBe(true);
+        expect(stringEquals("ABC", "abc", { ignoreCase: true })).toBe(true);
+    });
+});
+
+describe("capitalize", () => {
+    test("capitalizes the first letter of a string", () => {
+        expect(capitalize("abc")).toBe("Abc");
+    });
+
+    test("leaves the string as is if the first letter is already capitalized", () => {
+        expect(capitalize("Abc")).toBe("Abc");
+    });
+});
+
+describe("uncapitalize", () => {
+    test("uncapitalizes the first letter of a string", () => {
+        expect(uncapitalize("Abc")).toBe("abc");
+    });
+
+    test("leave the string as is if the first letter is already uncapitalized", () => {
+        expect(uncapitalize("abc")).toBe("abc");
+    });
+});
+
+describe("toPascalCase", () => {
+    test("converts strings to PascalCase", () => {
+        expect(toPascalCase("PascalCase")).toBe("PascalCase");
+        expect(toPascalCase("camelCase")).toBe("CamelCase");
+        expect(toPascalCase("kebab-case")).toBe("KebabCase");
+        expect(toPascalCase("snake_case")).toBe("SnakeCase");
+        expect(toPascalCase("SCREAMING_SNAKE_CASE")).toBe("ScreamingSnakeCase");
+    });
+});
+
+describe("split", () => {
+    describe("with string separator", () => {
+        test("splits a string by a given separator", () => {
+            expect(split("a,b,c", ",")).toEqual(["a", "b", "c"]);
+        });
+
+        test("removes empty entries if specified", () => {
+            expect(split("a,,b,,c", ",", { removeEmptyEntries: true })).toEqual(["a", "b", "c"]);
+        });
+
+        test("trims entries if specified", () => {
+            expect(split(" a , b ,  c  ", ",", { trimEntries: true })).toEqual(["a", "b", "c"]);
+        });
+    });
+
+    describe("with array of string separators", () => {
+        test("splits a string by a given separators", () => {
+            expect(split("a,b|c", [",", "|"])).toEqual(["a", "b", "c"]);
+        });
+
+        test("removes empty entries if specified", () => {
+            expect(split("a|,b,|c", [",", "|"], { removeEmptyEntries: true })).toEqual(["a", "b", "c"]);
+        });
+
+        test("trims entries if specified", () => {
+            expect(split(" a , b |  c  ", [",", "|"], { trimEntries: true })).toEqual(["a", "b", "c"]);
+        });
+    });
+
+    describe("with regex separator", () => {
+        test("splits a string by a given separator", () => {
+            expect(split("a1b2c", /\d/)).toEqual(["a", "b", "c"]);
+        });
+
+        test("removes empty entries if specified", () => {
+            expect(split("a12b34c5", /\d/, { removeEmptyEntries: true })).toEqual(["a", "b", "c"]);
+        });
+
+        test("trims entries if specified", () => {
+            expect(split(" a 1 b 2  c  ", /\d/, { trimEntries: true })).toEqual(["a", "b", "c"]);
+        });
+    });
+});
+
+describe("splitLines", () => {
+    test("splits a string into lines", () => {
+        expect(splitLines("a\nb\nc")).toEqual(["a", "b", "c"]);
+        expect(splitLines("a\r\nb\r\nc")).toEqual(["a", "b", "c"]);
+    });
+
+    test("splits a string into lines of a specified maximum length", () => {
+        expect(splitLines("abcd efg\nhijk lmn\nopq", { maxLength: 5 })).toEqual(["abcd", "efg", "hijk", "lmn", "opq"]);
+    });
+});
+
+describe("pad", () => {
+    test("pads a string to a given length", () => {
+        expect(pad("abc", 5)).toBe(" abc ");
+    });
+
+    test("pads a string with the given fill character", () => {
+        expect(pad("abc", 5, { fillString: "*" })).toBe("*abc*");
+    });
+
+    test("pads a string to the left", () => {
+        expect(pad("abc", 5, { align: "left" })).toBe("abc  ");
+    });
+
+    test("pads a string to the right", () => {
+        expect(pad("abc", 5, { align: "right" })).toBe("  abc");
+    });
+
+    test("pads a string to the center", () => {
+        expect(pad("abc", 5, { align: "center" })).toBe(" abc ");
+    });
+});
+
+describe("generateSecureRandomString", () => {
+    test("generates a random string of the specified length", () => {
+        expect(generateSecureRandomString(1)).toHaveLength(1);
+        expect(generateSecureRandomString(2)).toHaveLength(2);
+        expect(generateSecureRandomString(10)).toHaveLength(10);
+        expect(generateSecureRandomString(11)).toHaveLength(11);
+    });
+
+    test("returns an empty string if called with zero", () => {
+        expect(generateSecureRandomString(0)).toBe("");
+    });
+
+    test("generates different strings for different calls", () => {
+        expect(generateSecureRandomString(10)).not.toBe(generateSecureRandomString(10));
+    });
+});
+
+describe("hashString", () => {
+    test("hashes a string using the 'sha256' algorithm", () => {
+        const hashed = hashString("hello", "sha256");
+
+        expect(hashed).toBe(createHash("sha256").update("hello").digest("hex"));
+    });
+
+    test("hashes a string using the 'md5' algorithm", () => {
+        const hashed = hashString("hello", "md5");
+
+        expect(hashed).toBe(createHash("md5").update("hello").digest("hex"));
+    });
+
+    test("throws an error for an unknown algorithm", () => {
+        expect(() => hashString("hello", "unknown")).toThrow();
+    });
+});