oidc-provider/lib/helpers/constant_equals.js

OAuth 2.0 Authorization Server implementation for Node.js with OpenID Connect

import { timingSafeEqual } from 'node:crypto';

function paddedBuffer(string, length) {
  const buffer = Buffer.alloc(length, undefined, 'utf8');
  buffer.write(string);
  return buffer;
}

function constantEquals(a, b, minComp = 0) {
  if (!Number.isSafeInteger(minComp)) {
    throw new TypeError('minComp must be an Integer');
  }
  if (typeof a !== 'string' || typeof b !== 'string') {
    throw new TypeError('arguments must be strings');
  }
  const length = Math.max(a.length, b.length, minComp);
  return timingSafeEqual(paddedBuffer(a, length), paddedBuffer(b, length));
}

export default constantEquals;