feat: create new @jest/expect package

packages/expect/__typetests__/expect.test.ts

@@ -16,8 +16,7 @@ import {
 } from 'expect';
 import type * as jestMatcherUtils from 'jest-matcher-utils';
 
-type M = Matchers<void, unknown>;
-type N = Matchers<void>;
+type M = Matchers<void>;
 
 expectError(() => {
   type E = Matchers;

packages/expect/src/asymmetricMatchers.ts

@@ -62,22 +62,20 @@ export function hasProperty(obj: object | null, property: string): boolean {
   return hasProperty(getPrototype(obj), property);
 }
 
-export abstract class AsymmetricMatcher<
-  T,
-  State extends MatcherState = MatcherState,
-> implements AsymmetricMatcherInterface
+export abstract class AsymmetricMatcher<T>
+  implements AsymmetricMatcherInterface
 {
   $$typeof = Symbol.for('jest.asymmetricMatcher');
 
   constructor(protected sample: T, protected inverse = false) {}
 
-  protected getMatcherContext(): State {
+  protected getMatcherContext(): MatcherState {
     return {
       ...getState(),
       equals,
       isNot: this.inverse,
       utils,
-    } as State;
+    };
   }
 
   abstract asymmetricMatch(other: unknown): boolean;

packages/expect/src/index.ts

@@ -51,6 +51,7 @@ import type {
 
 export type {
   AsymmetricMatchers,
+  BaseExpect,
   Expect,
   MatcherFunction,
   MatcherFunctionWithState,
@@ -363,9 +364,8 @@ const makeThrowingMatcher = (
     }
   };
 
-expect.extend = <T extends MatcherState = MatcherState>(
-  matchers: MatchersObject<T>,
-) => setMatchers(matchers, false, expect);
+expect.extend = (matchers: MatchersObject) =>
+  setMatchers(matchers, false, expect);
 
 expect.anything = anything;
 expect.any = any;
@@ -431,7 +431,6 @@ setMatchers(matchers, true, expect);
 setMatchers(spyMatchers, true, expect);
 setMatchers(toThrowMatchers, true, expect);
 
-expect.addSnapshotSerializer = () => void 0;
 expect.assertions = assertions;
 expect.hasAssertions = hasAssertions;
 expect.getState = getState;

packages/expect/src/jestMatchersObject.ts

@@ -46,12 +46,11 @@ export const setState = <State extends MatcherState = MatcherState>(
   Object.assign((global as any)[JEST_MATCHERS_OBJECT].state, state);
 };
 
-export const getMatchers = <
-  State extends MatcherState = MatcherState,
->(): MatchersObject<State> => (global as any)[JEST_MATCHERS_OBJECT].matchers;
+export const getMatchers = (): MatchersObject =>
+  (global as any)[JEST_MATCHERS_OBJECT].matchers;
 
-export const setMatchers = <State extends MatcherState = MatcherState>(
-  matchers: MatchersObject<State>,
+export const setMatchers = (
+  matchers: MatchersObject,
   isInternal: boolean,
   expect: Expect,
 ): void => {
@@ -65,8 +64,7 @@ export const setMatchers = <State extends MatcherState = MatcherState>(
       // expect is defined
 
       class CustomMatcher extends AsymmetricMatcher<
-        [unknown, ...Array<unknown>],
-        State
+        [unknown, ...Array<unknown>]
       > {
         constructor(inverse = false, ...sample: [unknown, ...Array<unknown>]) {
           super(sample, inverse);

packages/expect/src/types.ts

@@ -35,8 +35,8 @@ export type RawMatcherFn<State extends MatcherState = MatcherState> = {
   [INTERNAL_MATCHER_FLAG]?: boolean;
 };
 
-export type MatchersObject<T extends MatcherState = MatcherState> = {
-  [name: string]: RawMatcherFn<T>;
+export type MatchersObject = {
+  [name: string]: RawMatcherFn;
 };
 
 export type ThrowingMatcherFn = (actual: any) => void;
@@ -76,27 +76,28 @@ export type ExpectedAssertionsErrors = Array<{
   expected: string;
 }>;
 
-export type Expect<State extends MatcherState = MatcherState> = {
-  <T = unknown>(actual: T): Matchers<void, T> &
-    InverseMatchers<void, T> &
-    PromiseMatchers<T>;
-  // TODO: this is added by test runners, not `expect` itself
-  addSnapshotSerializer(serializer: unknown): void;
+export type BaseExpect = {
   assertions(numberOfAssertions: number): void;
-  // TODO: remove this `T extends` - should get from some interface merging
-  extend<T extends MatcherState = State>(matchers: MatchersObject<T>): void;
+  extend(matchers: MatchersObject): void;
   extractExpectedAssertionsErrors(): ExpectedAssertionsErrors;
-  getState(): State;
+  getState(): MatcherState;
   hasAssertions(): void;
-  setState(state: Partial<State>): void;
-} & AsymmetricMatchers &
-  InverseAsymmetricMatchers;
+  setState(state: Partial<MatcherState>): void;
+};
+
+export type Expect = {
+  <T = unknown>(actual: T): Matchers<void> &
+    Inverse<Matchers<void>> &
+    PromiseMatchers;
+} & BaseExpect &
+  AsymmetricMatchers &
+  Inverse<Omit<AsymmetricMatchers, 'any' | 'anything'>>;
 
-type InverseAsymmetricMatchers = {
+type Inverse<Matchers> = {
   /**
    * Inverse next matcher. If you know how to test something, `.not` lets you test its opposite.
    */
-  not: Omit<AsymmetricMatchers, 'any' | 'anything'>;
+  not: Matchers;
 };
 
 export interface AsymmetricMatchers {
@@ -109,28 +110,21 @@ export interface AsymmetricMatchers {
   stringMatching(sample: string | RegExp): AsymmetricMatcher;
 }
 
-type PromiseMatchers<T = unknown> = {
+type PromiseMatchers = {
   /**
    * Unwraps the reason of a rejected promise so any other matcher can be chained.
    * If the promise is fulfilled the assertion fails.
    */
-  rejects: Matchers<Promise<void>, T> & InverseMatchers<Promise<void>, T>;
+  rejects: Matchers<Promise<void>> & Inverse<Matchers<Promise<void>>>;
   /**
    * Unwraps the value of a fulfilled promise so any other matcher can be chained.
    * If the promise is rejected the assertion fails.
    */
-  resolves: Matchers<Promise<void>, T> & InverseMatchers<Promise<void>, T>;
-};
-
-type InverseMatchers<R extends void | Promise<void>, T = unknown> = {
-  /**
-   * Inverse next matcher. If you know how to test something, `.not` lets you test its opposite.
-   */
-  not: Matchers<R, T>;
+  resolves: Matchers<Promise<void>> & Inverse<Matchers<Promise<void>>>;
 };
 
 // This is a copy from https://github.com/DefinitelyTyped/DefinitelyTyped/blob/de6730f4463cba69904698035fafd906a72b9664/types/jest/index.d.ts#L570-L817
-export interface Matchers<R extends void | Promise<void>, T = unknown> {
+export interface Matchers<R extends void | Promise<void>> {
   /**
    * Ensures the last call to a mock function was provided specific args.
    */
@@ -340,44 +334,4 @@ export interface Matchers<R extends void | Promise<void>, T = unknown> {
    * If you want to test that a specific error is thrown inside a function.
    */
   toThrowError(expected?: unknown): R;
-
-  /* TODO: START snapshot matchers are not from `expect`, the types should not be here */
-  /**
-   * This ensures that a value matches the most recent snapshot with property matchers.
-   * Check out [the Snapshot Testing guide](https://jestjs.io/docs/snapshot-testing) for more information.
-   */
-  toMatchSnapshot(hint?: string): R;
-  /**
-   * This ensures that a value matches the most recent snapshot.
-   * Check out [the Snapshot Testing guide](https://jestjs.io/docs/snapshot-testing) for more information.
-   */
-  toMatchSnapshot<U extends Record<keyof T, unknown>>(
-    propertyMatchers: Partial<U>,
-    hint?: string,
-  ): R;
-  /**
-   * This ensures that a value matches the most recent snapshot with property matchers.
-   * Instead of writing the snapshot value to a .snap file, it will be written into the source code automatically.
-   * Check out [the Snapshot Testing guide](https://jestjs.io/docs/snapshot-testing) for more information.
-   */
-  toMatchInlineSnapshot(snapshot?: string): R;
-  /**
-   * This ensures that a value matches the most recent snapshot with property matchers.
-   * Instead of writing the snapshot value to a .snap file, it will be written into the source code automatically.
-   * Check out [the Snapshot Testing guide](https://jestjs.io/docs/snapshot-testing) for more information.
-   */
-  toMatchInlineSnapshot<U extends Record<keyof T, unknown>>(
-    propertyMatchers: Partial<U>,
-    snapshot?: string,
-  ): R;
-  /**
-   * Used to test that a function throws a error matching the most recent snapshot when it is called.
-   */
-  toThrowErrorMatchingSnapshot(hint?: string): R;
-  /**
-   * Used to test that a function throws a error matching the most recent snapshot when it is called.
-   * Instead of writing the snapshot value to a .snap file, it will be written into the source code automatically.
-   */
-  toThrowErrorMatchingInlineSnapshot(snapshot?: string): R;
-  /* TODO: END snapshot matchers are not from `expect`, the types should not be here */
 }

packages/jest-circus/package.json

@@ -19,6 +19,7 @@
   },
   "dependencies": {
     "@jest/environment": "^28.0.0-alpha.1",
+    "@jest/expect": "^28.0.0-alpha.1",
     "@jest/test-result": "^28.0.0-alpha.1",
     "@jest/types": "^28.0.0-alpha.1",
     "@types/node": "*",

packages/jest-circus/src/legacy-code-todo-rewrite/jestAdapterInit.ts

@@ -7,6 +7,7 @@
 
 import throat from 'throat';
 import type {JestEnvironment} from '@jest/environment';
+import {type JestExpect, createJestExpect} from '@jest/expect';
 import {
   AssertionResult,
   Status,
@@ -15,7 +16,7 @@ import {
   createEmptyTestResult,
 } from '@jest/test-result';
 import type {Circus, Config, Global} from '@jest/types';
-import {Expect, expect} from 'expect';
+import {expect} from 'expect';
 import {bind} from 'jest-each';
 import {formatExecError, formatResultsErrors} from 'jest-message-util';
 import {
@@ -33,12 +34,9 @@ import {
 } from '../state';
 import testCaseReportHandler from '../testCaseReportHandler';
 import {getTestID} from '../utils';
-import createExpect from './jestExpect';
 
-type Process = NodeJS.Process;
-
-interface JestGlobals extends Global.TestFrameworkGlobals {
-  expect: Expect;
+interface RuntimeGlobals extends Global.TestFrameworkGlobals {
+  expect: JestExpect;
 }
 
 export const initialize = async ({
@@ -56,9 +54,9 @@ export const initialize = async ({
   globalConfig: Config.GlobalConfig;
   localRequire: <T = unknown>(path: Config.Path) => T;
   testPath: Config.Path;
-  parentProcess: Process;
+  parentProcess: NodeJS.Process;
   sendMessageToJest?: TestFileEvent;
-  setGlobalsForRuntime: (globals: JestGlobals) => void;
+  setGlobalsForRuntime: (globals: RuntimeGlobals) => void;
 }): Promise<{
   globals: Global.TestFrameworkGlobals;
   snapshotState: SnapshotState;
@@ -124,9 +122,9 @@ export const initialize = async ({
     addEventHandler(environment.handleTestEvent.bind(environment));
   }
 
-  const runtimeGlobals: JestGlobals = {
+  const runtimeGlobals: RuntimeGlobals = {
     ...globalsObject,
-    expect: createExpect(globalConfig),
+    expect: createJestExpect(globalConfig),
   };
   setGlobalsForRuntime(runtimeGlobals);
 
@@ -161,7 +159,7 @@ export const initialize = async ({
     snapshotFormat: config.snapshotFormat,
     updateSnapshot,
   });
-  // @ts-expect-error: snapshotState is a jest extension of `expect`
+
   expect.setState({snapshotState, testPath});
 
   addEventHandler(handleSnapshotStateAfterRetry(snapshotState));

packages/jest-circus/tsconfig.json

@@ -10,6 +10,7 @@
     {"path": "../expect"},
     {"path": "../jest-each"},
     {"path": "../jest-environment"},
+    {"path": "../jest-expect"},
     {"path": "../jest-matcher-utils"},
     {"path": "../jest-message-util"},
     {"path": "../jest-runtime"},

packages/jest-expect/.npmignore

@@ -0,0 +1,5 @@
+**/__tests__/**
+src
+tsconfig.json
+tsconfig.tsbuildinfo
+api-extractor.json

packages/jest-expect/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "@jest/expect",
+  "version": "28.0.0-alpha.1",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/facebook/jest.git",
+    "directory": "packages/jest-expect"
+  },
+  "license": "MIT",
+  "main": "./build/index.js",
+  "types": "./build/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./build/index.d.ts",
+      "default": "./build/index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "dependencies": {
+    "@jest/types": "^28.0.0-alpha.1",
+    "expect": "^28.0.0-alpha.1",
+    "jest-snapshot": "^28.0.0-alpha.1"
+  },
+  "engines": {
+    "node": "^12.13.0 || ^14.15.0 || ^16.13.0 || >=17.0.0"
+  },
+  "publishConfig": {
+    "access": "public"
+  }
+}

packages/jest-circus/src/legacy-code-todo-rewrite/jestExpect.ts → packages/jest-expect/src/index.ts

@@ -6,27 +6,30 @@
  */
 
 import type {Config} from '@jest/types';
-import {Expect, expect} from 'expect';
+import {expect} from 'expect';
 import {
   addSerializer,
   toMatchInlineSnapshot,
   toMatchSnapshot,
   toThrowErrorMatchingInlineSnapshot,
   toThrowErrorMatchingSnapshot,
 } from 'jest-snapshot';
+import type {JestExpect} from './types';
 
-export default function jestExpect(
-  config: Pick<Config.GlobalConfig, 'expand'>,
-): Expect {
-  expect.setState({expand: config.expand});
-  expect.extend({
+export type {JestExpect} from './types';
+
+export function createJestExpect({expand}: Config.GlobalConfig): JestExpect {
+  const jestExpect = expect as JestExpect;
+
+  jestExpect.setState({expand});
+  jestExpect.extend({
     toMatchInlineSnapshot,
     toMatchSnapshot,
     toThrowErrorMatchingInlineSnapshot,
     toThrowErrorMatchingSnapshot,
   });
 
-  expect.addSnapshotSerializer = addSerializer;
+  jestExpect.addSnapshotSerializer = addSerializer;
 
-  return expect;
+  return jestExpect;
 }