first commit

lib/utils/base64.ts

@@ -0,0 +1,17 @@
+export function base64UrlEncode(buf: Buffer | string) {
+	const s = typeof buf === 'string' ? Buffer.from(buf) : buf
+
+	return s
+		.toString('base64')
+		.replace(/\+/g, '-')
+		.replace(/\//g, '_')
+		.replace(/=+$/, '')
+}
+
+export function base64UrlDecode(str: string) {
+	str = str.replace(/-/g, '+').replace(/_/g, '/')
+
+	while (str.length % 4) str += '='
+
+	return Buffer.from(str, 'base64').toString()
+}

lib/utils/crypto.ts

@@ -0,0 +1,10 @@
+import { timingSafeEqual } from 'crypto'
+
+export function constantTimeEqual(a: string, b: string) {
+	const bufA = Buffer.from(a)
+	const bufB = Buffer.from(b)
+
+	if (bufA.length !== bufB.length) return false
+
+	return timingSafeEqual(bufA, bufB)
+}

lib/utils/index.ts

@@ -0,0 +1,2 @@
+export * from './base64'
+export * from './crypto'