chore: BigInt is always defined, do not conditionally check for it (#11979)

Author: SimenB

.eslintrc.js

@@ -26,6 +26,9 @@ module.exports = {
     'plugin:eslint-comments/recommended',
     'plugin:prettier/recommended',
   ],
+  globals: {
+    BigInt: 'readonly',
+  },
   overrides: [
     {
       extends: [

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ### Chore & Maintenance
 
+- `[expect]` `BigInt` global is always defined, don't check for its existence at runtime ([#11979](https://github.com/facebook/jest/pull/11979))
 - `[jest-config, jest-util]` Use `ci-info` instead of `is-ci` to detect CI environment ([#11973](https://github.com/facebook/jest/pull/11973))
 
 ### Performance

packages/expect/src/__tests__/asymmetricMatchers.test.ts

@@ -28,7 +28,6 @@ test('Any.asymmetricMatch()', () => {
     any(Number).asymmetricMatch(1),
     any(Function).asymmetricMatch(() => {}),
     any(Boolean).asymmetricMatch(true),
-    /* global BigInt */
     any(BigInt).asymmetricMatch(1n),
     any(Symbol).asymmetricMatch(Symbol()),
     any(Object).asymmetricMatch({}),
@@ -50,7 +49,6 @@ test('Any.asymmetricMatch() on primitive wrapper classes', () => {
     any(Function).asymmetricMatch(new Function('() => {}')),
     // eslint-disable-next-line no-new-wrappers
     any(Boolean).asymmetricMatch(new Boolean(true)),
-    /* global BigInt */
     any(BigInt).asymmetricMatch(Object(1n)),
     any(Symbol).asymmetricMatch(Object(Symbol())),
   ].forEach(test => {