fix: global detection in a browser worker runtime

src/.eslintrc.json

@@ -31,8 +31,11 @@
     "jsdoc/require-param": 2,
     "jsdoc/valid-types": 2
   },
-  "globals": {
-    "window": "readonly"
-  },
-  "ignorePatterns": ["src/runtime/*/*.ts", "src/runtime/webcrypto.ts", "dist", "src/runtime/*.d.ts"]
+  "ignorePatterns": [
+    "src/runtime/*/*.ts",
+    "src/runtime/webcrypto.ts",
+    "src/runtime/global.ts",
+    "dist",
+    "src/runtime/*.d.ts"
+  ]
 }

src/runtime/browser/base64url.ts

@@ -1,12 +1,13 @@
 import type { Base64UrlDecode, Base64UrlEncode } from '../interfaces.d'
 import { encoder, decoder } from '../../lib/buffer_utils.js'
+import globalThis from './global.js'
 
 export const encode: Base64UrlEncode = (input) => {
   let unencoded = input
   if (typeof unencoded === 'string') {
     unencoded = encoder.encode(unencoded)
   }
-  const base64string = window.btoa(String.fromCharCode.apply(0, [...unencoded]))
+  const base64string = globalThis.btoa(String.fromCharCode.apply(0, [...unencoded]))
   return base64string.replace(/=/g, '').replace(/\+/g, '-').replace(/\//g, '_')
 }
 
@@ -17,7 +18,7 @@ export const decode: Base64UrlDecode = (input) => {
   }
   encoded = encoded.replace(/-/g, '+').replace(/_/g, '/').replace(/\s/g, '')
   return new Uint8Array(
-    window
+    globalThis
       .atob(encoded)
       .split('')
       .map((c) => c.charCodeAt(0)),

src/runtime/browser/fetch.ts

@@ -1,5 +1,6 @@
 import type { FetchFunction } from '../interfaces.d'
 import { JOSEError } from '../../util/errors.js'
+import globalThis from './global.js'
 
 const fetch: FetchFunction = async (url: URL, timeout: number) => {
   let controller!: AbortController
@@ -8,7 +9,7 @@ const fetch: FetchFunction = async (url: URL, timeout: number) => {
     setTimeout(() => controller.abort(), timeout)
   }
 
-  const response = await window.fetch(url.href, {
+  const response = await globalThis.fetch(url.href, {
     signal: controller ? controller.signal : undefined,
     redirect: 'manual',
     referrerPolicy: 'no-referrer',

src/runtime/browser/global.ts

@@ -0,0 +1,9 @@
+/* eslint-disable no-restricted-globals */
+
+function getGlobal() {
+  if (typeof self !== 'undefined') return self
+  if (typeof window !== 'undefined') return window
+  throw new Error('unable to locate global object')
+}
+
+export default globalThis || getGlobal()

src/runtime/browser/webcrypto.ts

@@ -1,10 +1,9 @@
 import { JOSEError } from '../../util/errors.js'
+import globalThis from './global.js'
 
-const { crypto } = window
-
-export default crypto
+export default globalThis.crypto
 export function ensureSecureContext() {
-  if (!window.isSecureContext && !crypto.subtle) {
+  if (!globalThis.isSecureContext && !globalThis.crypto.subtle) {
     throw new JOSEError(
       'Web Cryptography API is available only in Secure Contexts. See: https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts',
     )