fix: lazily define node env globals (#12696)

jestjs · Apr 20, 2022 · 78d4088 · 78d4088
1 parent 58af3c1
commit 78d4088
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Showing 2 changed files with 47 additions and 8 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -26,7 +26,7 @@
 - `[jest-environment-node]` [**BREAKING**] Add default `node` and `node-addon` conditions to `exportConditions` for `node` environment ([#11924](https://github.com/facebook/jest/pull/11924))
 - `[jest-environment-node]` [**BREAKING**] Pass global config to Jest environment constructor for `node` environment ([#12461](https://github.com/facebook/jest/pull/12461))
 - `[jest-environment-node]` [**BREAKING**] Second argument `context` to constructor is mandatory ([#12469](https://github.com/facebook/jest/pull/12469))
-- `[jest-environment-node]` Add all available globals to test globals, not just explicit ones ([#12642](https://github.com/facebook/jest/pull/12642))
+- `[jest-environment-node]` Add all available globals to test globals, not just explicit ones ([#12642](https://github.com/facebook/jest/pull/12642), [#12696](https://github.com/facebook/jest/pull/12696))
 - `[@jest/expect]` New module which extends `expect` with `jest-snapshot` matchers ([#12404](https://github.com/facebook/jest/pull/12404), [#12410](https://github.com/facebook/jest/pull/12410), [#12418](https://github.com/facebook/jest/pull/12418))
 - `[@jest/expect-utils]` New module exporting utils for `expect` ([#12323](https://github.com/facebook/jest/pull/12323))
 - `[@jest/fake-timers]` [**BREAKING**] Rename `timers` configuration option to `fakeTimers` ([#12572](https://github.com/facebook/jest/pull/12572))

diff --git a/packages/jest-environment-node/src/index.ts b/packages/jest-environment-node/src/index.ts
@@ -30,12 +30,27 @@ const denyList = new Set([
   'Buffer',
   'ArrayBuffer',
   'Uint8Array',
+  // if env is loaded within a jest test
+  'jest-symbol-do-not-touch',
 ]);
 
-const nodeGlobals = new Set(
-  Object.getOwnPropertyNames(globalThis).filter(
-    global => !denyList.has(global),
-  ),
+const nodeGlobals = new Map(
+  Object.getOwnPropertyNames(globalThis)
+    .filter(global => !denyList.has(global))
+    .map(nodeGlobalsKey => {
+      const descriptor = Object.getOwnPropertyDescriptor(
+        globalThis,
+        nodeGlobalsKey,
+      );
+
+      if (!descriptor) {
+        throw new Error(
+          `No property descriptor for ${nodeGlobalsKey}, this is a bug in Jest.`,
+        );
+      }
+
+      return [nodeGlobalsKey, descriptor];
+    }),
 );
 
 export default class NodeEnvironment implements JestEnvironment<Timer> {
@@ -55,10 +70,34 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
     ));
 
     const contextGlobals = new Set(Object.getOwnPropertyNames(global));
-    for (const nodeGlobalsKey of nodeGlobals) {
+    for (const [nodeGlobalsKey, descriptor] of nodeGlobals) {
       if (!contextGlobals.has(nodeGlobalsKey)) {
-        // @ts-expect-error
-        global[nodeGlobalsKey] = globalThis[nodeGlobalsKey];
+        Object.defineProperty(global, nodeGlobalsKey, {
+          configurable: descriptor.configurable,
+          enumerable: descriptor.enumerable,
+          get() {
+            // @ts-expect-error
+            const val = globalThis[nodeGlobalsKey];
+
+            // override lazy getter
+            Object.defineProperty(global, nodeGlobalsKey, {
+              configurable: descriptor.configurable,
+              enumerable: descriptor.enumerable,
+              value: val,
+              writable: descriptor.writable,
+            });
+            return val;
+          },
+          set(val) {
+            // override lazy getter
+            Object.defineProperty(global, nodeGlobalsKey, {
+              configurable: descriptor.configurable,
+              enumerable: descriptor.enumerable,
+              value: val,
+              writable: true,
+            });
+          },
+        });
       }
     }