fix: make globalThis more compatible with jest

packages/vitest/src/integrations/chai/constants.ts

@@ -1,2 +1,3 @@
 export const GLOBAL_EXPECT = Symbol.for('expect-global')
 export const MATCHERS_OBJECT = Symbol.for('matchers-object')
+export const JEST_MATCHERS_OBJECT = Symbol.for('$$jest-matchers-object')

packages/vitest/src/integrations/chai/jest-asymmetric-matchers.ts

@@ -16,6 +16,7 @@ export abstract class AsymmetricMatcher<
   T,
   State extends MatcherState = MatcherState,
 > implements AsymmetricMatcherInterface {
+  // should have "jest" to be compatible with its ecosystem
   $$typeof = Symbol.for('jest.asymmetricMatcher')
 
   constructor(protected sample: T, protected inverse = false) {}

packages/vitest/src/integrations/chai/jest-expect.ts

@@ -10,11 +10,20 @@ import type { ChaiPlugin, MatcherState } from '../../types/chai'
 import { arrayBufferEquality, generateToBeMessage, iterableEquality, equals as jestEquals, sparseArrayEquality, subsetEquality, typeEquality } from './jest-utils'
 import type { AsymmetricMatcher } from './jest-asymmetric-matchers'
 import { stringify } from './jest-matcher-utils'
-import { MATCHERS_OBJECT } from './constants'
+import { GLOBAL_EXPECT, JEST_MATCHERS_OBJECT, MATCHERS_OBJECT } from './constants'
 
 if (!Object.prototype.hasOwnProperty.call(globalThis, MATCHERS_OBJECT)) {
+  const globalState = new WeakMap<Vi.ExpectStatic, MatcherState>()
+  const matchers = Object.create(null)
   Object.defineProperty(globalThis, MATCHERS_OBJECT, {
-    value: new WeakMap<Vi.ExpectStatic, MatcherState>(),
+    get: () => globalState,
+  })
+  Object.defineProperty(globalThis, JEST_MATCHERS_OBJECT, {
+    configurable: true,
+    get: () => ({
+      state: globalState.get((globalThis as any)[GLOBAL_EXPECT]),
+      matchers,
+    }),
   })
 }
 
@@ -36,6 +45,7 @@ export const JestChaiExpect: ChaiPlugin = (chai, utils) => {
   function def(name: keyof Vi.Assertion | (keyof Vi.Assertion)[], fn: ((this: Chai.AssertionStatic & Vi.Assertion, ...args: any[]) => any)) {
     const addMethod = (n: keyof Vi.Assertion) => {
       utils.addMethod(chai.Assertion.prototype, n, fn)
+      utils.addMethod((globalThis as any)[JEST_MATCHERS_OBJECT].matchers, n, fn)
     }
 
     if (Array.isArray(name))

packages/vitest/src/integrations/chai/jest-extend.ts

@@ -6,6 +6,7 @@ import type {
   SyncExpectationResult,
 } from '../../types/chai'
 import { getSnapshotClient } from '../snapshot/chai'
+import { JEST_MATCHERS_OBJECT } from './constants'
 import { AsymmetricMatcher } from './jest-asymmetric-matchers'
 import { getState } from './jest-expect'
 
@@ -79,6 +80,7 @@ function JestExtendPlugin(expect: Vi.ExpectStatic, matchers: MatchersObject): Ch
 
       const expectAssertionWrapper = isAsyncFunction(expectAssertion) ? expectAsyncWrapper : expectSyncWrapper
 
+      utils.addMethod((globalThis as any)[JEST_MATCHERS_OBJECT].matchers, expectAssertionName, expectAssertionWrapper)
       utils.addMethod(c.Assertion.prototype, expectAssertionName, expectAssertionWrapper)
 
       class CustomMatcher extends AsymmetricMatcher<[unknown, ...unknown[]]> {

test/core/test/jest-expect.test.ts

@@ -603,4 +603,16 @@ describe('async expect', () => {
   })
 })
 
+it('compatible with jest', () => {
+  expect.extend({
+    someObject() {
+      return { pass: true, message: () => '' }
+    },
+  })
+  const { matchers, state } = (globalThis as any)[Symbol.for('$$jest-matchers-object')]
+  expect(matchers).toHaveProperty('someObject')
+  expect(matchers).toHaveProperty('toBe')
+  expect(state.assertionCalls).toBe(2)
+})
+
 it('timeout', () => new Promise(resolve => setTimeout(resolve, 500)))