Uses the SubtleCrypto interface of the Web Cryptography API to hash a message using SHA-256.

crypto-sha.js

/**
 * Returns SHA-256 hash from supplied message.
 *
 * @param   {String} message.
 * @returns {String} hash as hex string.
 *
 * @example
 *   sha256('abc').then(hash => console.log(hash));
 *   const hash = await sha256('abc');
 */
async function sha256(message) {
    const msgUint8 = new TextEncoder().encode(message);                           // encode as (utf-8) Uint8Array
    const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);           // hash the message
    const hashArray = Array.from(new Uint8Array(hashBuffer));                     // convert buffer to byte array
    const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join(''); // convert bytes to hex string
    return hashHex;
}