sha256

1/**
2 * Generates a SHA-256 hash of the input string.
3 *
4 * @param input - The input string to hash.
5 * @returns A Promise that resolves to the hex-encoded SHA-256 hash.
6 */
7export async function sha256(input: string): Promise<string> {
8  const encoder = new TextEncoder();
9  const data = encoder.encode(input);
10  const hashBuffer = await crypto.subtle.digest('SHA-256', data);
11  const hashArray = Array.from(new Uint8Array(hashBuffer));
12  return hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
13}

• Strong Cryptographic Hashing

  Utilizes the SHA-256 algorithm, which is part of the SHA-2 family and widely trusted for data integrity and digital signatures.

• Browser-Native Web Crypto API

  Leverages crypto.subtle.digest, ensuring modern, secure, and performant hashing without third-party libraries.

• Hex-Encoded Output

  Converts the binary digest to a lowercase hexadecimal string, making it human-readable and easy to store or transmit.

• Asynchronous Execution

  Uses Promise-based design to avoid blocking the main thread, suitable for performance-critical applications.

• Cross-Platform Compatibility

  Runs in all modern browsers and environments that support the Web Crypto API, including many desktop and mobile contexts.

Tests | Examples

1import { sha256 } from './sha256';
2
3test('sha256 - hashes known value', async () => {
4  const hash = await sha256('hello');
5  expect(hash).toBe('2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824');
6});
7
8test('sha256 - produces different hashes for different inputs', async () => {
9  const hash1 = await sha256('apple');
10  const hash2 = await sha256('banana');
11  expect(hash1).not.toBe(hash2);
12});
13
14test('sha256 - empty string hash', async () => {
15  const hash = await sha256('');
16  expect(hash).toBe('e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855');
17});

Common Use Cases

• Password Hashing for Storage or Comparison

  Transform plaintext credentials into fixed-length hashes before verification or local storage (with salt in real-world scenarios).

• Data Integrity Checks

  Generate hashes to verify whether files, payloads, or responses have been tampered with.

• Digital Signatures or Tokens

  Use hashes as part of token signing or for deterministic value generation in client-authenticated flows.

• Cache Keys and ETag Generation

  Create unique, reproducible keys based on content for caching systems or HTTP ETag headers.

• Fingerprinting or De-duplication

  Detect duplicate content or uniquely identify resources based on their hashed value.