Adjust & dedupe global extraction tests (#1301)

CHANGELOG.md

@@ -11,6 +11,7 @@ Changes:
 - Expose `assertUnreachable` for codepaths that should not be followed
 - Swap to upstream `@noble/hashes`
 - Preserve all-caps word splits in `stringCamelCase`
+- Adjust `x-*` fallbacks via `x-global/extractGlobal`
 - Sync with upstream Substrate ss58 registry
 - Maintainability cleanups
 

packages/x-bigint/src/shim.ts

@@ -2,8 +2,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { BigInt } from '@polkadot/x-bigint';
-import { xglobal } from '@polkadot/x-global';
+import { exposeGlobal } from '@polkadot/x-global';
 
-if (typeof xglobal.BigInt !== 'function') {
-  (xglobal as Record<string, unknown>).BigInt = BigInt;
-}
+exposeGlobal('BigInt', BigInt);

packages/x-fetch/src/node.ts

@@ -3,12 +3,8 @@
 
 import nodeFetch from 'node-fetch';
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 export { packageInfo } from './packageInfo';
 
-export const fetch = (
-  typeof xglobal.fetch === 'undefined'
-    ? nodeFetch as unknown as typeof global.fetch
-    : xglobal.fetch
-);
+export const fetch = extractGlobal('fetch', nodeFetch);

packages/x-fetch/src/shim.ts

@@ -2,8 +2,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { fetch } from '@polkadot/x-fetch';
-import { xglobal } from '@polkadot/x-global';
+import { exposeGlobal } from '@polkadot/x-global';
 
-if (typeof xglobal.fetch !== 'function') {
-  (xglobal as Record<string, unknown>).fetch = fetch;
-}
+exposeGlobal('fetch', fetch);

packages/x-global/src/index.ts

@@ -5,6 +5,10 @@ export { packageInfo } from './packageInfo';
 
 type GlobalThis = typeof globalThis;
 
+type GlobalNames = keyof typeof window;
+
+type GlobalType<T extends keyof typeof window> = typeof window[T];
+
 function evaluateThis (fn: (code: string) => unknown): GlobalThis {
   return fn('return this') as GlobalThis;
 }
@@ -20,3 +24,15 @@ export const xglobal = (
           ? window
           : evaluateThis(Function)
 );
+
+export function extractGlobal <N extends GlobalNames, T extends GlobalType<N>> (name: N, fallback: unknown): T {
+  return typeof xglobal[name as 'undefined'] === 'undefined'
+    ? fallback as T
+    : xglobal[name as 'undefined'] as unknown as T;
+}
+
+export function exposeGlobal <N extends GlobalNames> (name: N, fallback: unknown): void {
+  if (typeof xglobal[name as 'undefined'] === 'undefined') {
+    xglobal[name as 'undefined'] = fallback as undefined;
+  }
+}

packages/x-textdecoder/src/browser.ts

@@ -1,14 +1,10 @@
 // Copyright 2017-2021 @polkadot/x-textencoder authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 import { TextDecoder as Fallback } from './fallback';
 
 export { packageInfo } from './packageInfo';
 
-export const TextDecoder = (
-  typeof xglobal.TextDecoder === 'undefined'
-    ? Fallback as unknown as typeof xglobal.TextDecoder
-    : xglobal.TextDecoder
-);
+export const TextDecoder = extractGlobal('TextDecoder', Fallback);

packages/x-textdecoder/src/node.ts

@@ -3,12 +3,8 @@
 
 import util from 'util';
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 export { packageInfo } from './packageInfo';
 
-export const TextDecoder = (
-  typeof xglobal.TextDecoder === 'undefined'
-    ? util.TextDecoder as unknown as typeof xglobal.TextDecoder
-    : xglobal.TextDecoder
-);
+export const TextDecoder = extractGlobal('TextDecoder', util.TextDecoder);

packages/x-textdecoder/src/shim.ts

@@ -1,9 +1,7 @@
 // Copyright 2017-2021 @polkadot/x-textdecoder authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { xglobal } from '@polkadot/x-global';
+import { exposeGlobal } from '@polkadot/x-global';
 import { TextDecoder } from '@polkadot/x-textdecoder';
 
-if (typeof xglobal.TextDecoder !== 'function') {
-  (xglobal as Record<string, unknown>).TextDecoder = TextDecoder;
-}
+exposeGlobal('TextDecoder', TextDecoder);

packages/x-textencoder/src/browser.ts

@@ -1,14 +1,10 @@
 // Copyright 2017-2021 @polkadot/x-textencoder authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 import { TextEncoder as Fallback } from './fallback';
 
 export { packageInfo } from './packageInfo';
 
-export const TextEncoder = (
-  typeof xglobal.TextEncoder === 'undefined'
-    ? Fallback as unknown as typeof xglobal.TextEncoder
-    : xglobal.TextEncoder
-);
+export const TextEncoder = extractGlobal('TextEncoder', Fallback);

packages/x-textencoder/src/node.ts

@@ -3,11 +3,11 @@
 
 import util from 'util';
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 export { packageInfo } from './packageInfo';
 
-class NodeFallback {
+class Fallback {
   #encoder: util.TextEncoder;
 
   constructor () {
@@ -20,8 +20,4 @@ class NodeFallback {
   }
 }
 
-export const TextEncoder = (
-  typeof xglobal.TextEncoder === 'undefined'
-    ? NodeFallback as unknown as typeof xglobal.TextEncoder
-    : xglobal.TextEncoder
-);
+export const TextEncoder = extractGlobal('TextEncoder', Fallback);

packages/x-textencoder/src/shim.ts

@@ -1,9 +1,7 @@
 // Copyright 2017-2021 @polkadot/x-textencoder authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { xglobal } from '@polkadot/x-global';
+import { exposeGlobal } from '@polkadot/x-global';
 import { TextEncoder } from '@polkadot/x-textencoder';
 
-if (typeof xglobal.TextEncoder !== 'function') {
-  (xglobal as Record<string, unknown>).TextEncoder = TextEncoder;
-}
+exposeGlobal('TextEncoder', TextEncoder);

packages/x-ws/src/node.ts

@@ -3,12 +3,8 @@
 
 import ws from 'websocket';
 
-import { xglobal } from '@polkadot/x-global';
+import { extractGlobal } from '@polkadot/x-global';
 
 export { packageInfo } from './packageInfo';
 
-export const WebSocket = (
-  typeof xglobal.WebSocket === 'undefined'
-    ? ws.w3cwebsocket as unknown as typeof xglobal.WebSocket
-    : xglobal.WebSocket
-);
+export const WebSocket = extractGlobal('WebSocket', ws.w3cwebsocket);

packages/x-ws/src/shim.ts

@@ -1,9 +1,7 @@
 // Copyright 2017-2021 @polkadot/x-ws authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { xglobal } from '@polkadot/x-global';
+import { exposeGlobal } from '@polkadot/x-global';
 import { WebSocket } from '@polkadot/x-ws';
 
-if (typeof xglobal.WebSocket !== 'function') {
-  (xglobal as Record<string, unknown>).WebSocket = WebSocket;
-}
+exposeGlobal('WebSocket', WebSocket);