Be more defensive against find/replace __DEV__ minifiers.

#8347 (comment)

src/utilities/globals/__DEV__.ts → src/utilities/globals/DEV.ts

@@ -1,11 +1,17 @@
 import global from "../common/global";
 import { maybe } from "../common/maybe";
 
+// To keep string-based find/replace minifiers from messing with __DEV__ inside
+// string literals or properties like global.__DEV__, we construct the "__DEV__"
+// string in a roundabout way that won't be altered by find/replace strategies.
+const __ = "__";
+const GLOBAL_KEY = [__, __].join("DEV");
+
 function getDEV() {
   try {
     return Boolean(__DEV__);
   } catch {
-    Object.defineProperty(global, "__DEV__", {
+    Object.defineProperty(global, GLOBAL_KEY, {
       // In a buildless browser environment, maybe(() => process.env.NODE_ENV)
       // evaluates as undefined, so __DEV__ becomes true by default, but can be
       // initialized to false instead by a script/module that runs earlier.
@@ -14,7 +20,9 @@ function getDEV() {
       configurable: true,
       writable: true,
     });
-    return global.__DEV__;
+    // Using computed property access rather than global.__DEV__ here prevents
+    // string-based find/replace strategies from munging this to global.false:
+    return (global as any)[GLOBAL_KEY];
   }
 }
 

src/utilities/globals/index.ts

@@ -1,6 +1,6 @@
 // Just in case the graphql package switches from process.env.NODE_ENV to
 // __DEV__, make sure __DEV__ is polyfilled before importing graphql.
-import DEV from "./__DEV__";
+import DEV from "./DEV";
 export { DEV }
 
 // Import graphql/jsutils/instanceOf safely, working around its unchecked usage