feat: optimize lookup speed by doing it once

Author: logaretm

packages/core/src/utils/randomSafeContext.ts

@@ -2,26 +2,28 @@ import { GLOBAL_OBJ } from './worldwide';
 
 export type RandomSafeContextRunner = <T>(callback: () => T) => T;
 
-let RESOLVED_RUNNER: RandomSafeContextRunner | undefined;
+// undefined = not yet resolved, null = no runner found, function = runner found
+let RESOLVED_RUNNER: RandomSafeContextRunner | null | undefined;
 
 /**
  * Simple wrapper that allows SDKs to *secretly* set context wrapper to generate safe random IDs in cache components contexts
  */
 export function withRandomSafeContext<T>(cb: () => T): T {
-  // Skips future symbol lookups if we've already resolved the runner once
-  if (RESOLVED_RUNNER) {
-    return RESOLVED_RUNNER(cb);
+  // Skips future symbol lookups if we've already resolved (or attempted to resolve) the runner once
+  if (RESOLVED_RUNNER !== undefined) {
+    return RESOLVED_RUNNER ? RESOLVED_RUNNER(cb) : cb();
   }
 
   const sym = Symbol.for('__SENTRY_SAFE_RANDOM_ID_WRAPPER__');
   const globalWithSymbol: typeof GLOBAL_OBJ & { [sym]?: RandomSafeContextRunner } = GLOBAL_OBJ;
-  if (!(sym in globalWithSymbol) || typeof globalWithSymbol[sym] !== 'function') {
-    return cb();
-  }
 
-  RESOLVED_RUNNER = globalWithSymbol[sym];
+  if (sym in globalWithSymbol && typeof globalWithSymbol[sym] === 'function') {
+    RESOLVED_RUNNER = globalWithSymbol[sym];
+    return RESOLVED_RUNNER(cb);
+  }
 
-  return globalWithSymbol[sym](cb);
+  RESOLVED_RUNNER = null;
+  return cb();
 }
 
 /**