expect
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text/typescript
import { EqualsFunction, Tester, Tester as Tester$1, TesterContext } from "@jest/expect-utils";
import * as jestMatcherUtils from "jest-matcher-utils";
import { MockInstance } from "jest-mock";
//#region src/types.d.ts
type SyncExpectationResult = {
pass: boolean;
message(): string;
};
type AsyncExpectationResult = Promise<SyncExpectationResult>;
type ExpectationResult = SyncExpectationResult | AsyncExpectationResult;
type MatcherFunctionWithContext<Context extends MatcherContext = MatcherContext, Expected extends Array<any> = [] /** TODO should be: extends Array<unknown> = [] */> = (this: Context, actual: unknown, ...expected: Expected) => ExpectationResult;
type MatcherFunction<Expected extends Array<unknown> = []> = MatcherFunctionWithContext<MatcherContext, Expected>;
type RawMatcherFn<Context extends MatcherContext = MatcherContext> = {
(this: Context, actual: any, ...expected: Array<any>): ExpectationResult;
};
type MatchersObject = {
[name: string]: RawMatcherFn;
};
interface MatcherUtils {
customTesters: Array<Tester$1>;
dontThrow(): void;
equals: EqualsFunction;
utils: typeof jestMatcherUtils & {
iterableEquality: Tester$1;
subsetEquality: Tester$1;
};
}
interface MatcherState {
assertionCalls: number;
currentConcurrentTestName?: () => string | undefined;
currentTestName?: string;
error?: Error;
expand?: boolean;
expectedAssertionsNumber: number | null;
expectedAssertionsNumberError?: Error;
isExpectingAssertions: boolean;
isExpectingAssertionsError?: Error;
isNot?: boolean;
numPassingAsserts: number;
promise?: string;
suppressedErrors: Array<Error>;
testPath?: string;
}
type MatcherContext = MatcherUtils & Readonly<MatcherState>;
type AsymmetricMatcher$1 = {
asymmetricMatch(other: unknown): boolean;
toString(): string;
getExpectedType?(): string;
toAsymmetricMatcher?(): string;
};
type ExpectedAssertionsErrors = Array<{
actual: string | number;
error: Error;
expected: string;
}>;
interface BaseExpect {
assertions(numberOfAssertions: number): void;
addEqualityTesters(testers: Array<Tester$1>): void;
extend(matchers: MatchersObject): void;
extractExpectedAssertionsErrors(): ExpectedAssertionsErrors;
getState(): MatcherState;
hasAssertions(): void;
setState(state: Partial<MatcherState>): void;
}
type Expect = (<T = unknown>(actual: T) => Matchers<void, T> & Inverse<Matchers<void, T>> & PromiseMatchers<T>) & BaseExpect & AsymmetricMatchers & Inverse<Omit<AsymmetricMatchers, 'any' | 'anything'>>;
type Inverse<Matchers> = {
/**
* Inverse next matcher. If you know how to test something, `.not` lets you test its opposite.
*/
not: Matchers;
};
interface AsymmetricMatchers {
any(sample: unknown): AsymmetricMatcher$1;
anything(): AsymmetricMatcher$1;
arrayContaining(sample: Array<unknown>): AsymmetricMatcher$1;
arrayOf(sample: unknown): AsymmetricMatcher$1;
closeTo(sample: number, precision?: number): AsymmetricMatcher$1;
objectContaining(sample: Record<string, unknown>): AsymmetricMatcher$1;
stringContaining(sample: string): AsymmetricMatcher$1;
stringMatching(sample: string | RegExp): AsymmetricMatcher$1;
}
type PromiseMatchers<T = unknown> = {
/**
* 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> & Inverse<Matchers<Promise<void>, T>>;
/**
* 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> & Inverse<Matchers<Promise<void>, T>>;
};
interface Matchers<R extends void | Promise<void>, T = unknown> {
/**
* Checks that a value is what you expect. It calls `Object.is` to compare values.
* Don't use `toBe` with floating-point numbers.
*/
toBe(expected: unknown): R;
/**
* Using exact equality with floating point numbers is a bad idea.
* Rounding means that intuitive things fail.
* The default for `precision` is 2.
*/
toBeCloseTo(expected: number, precision?: number): R;
/**
* Ensure that a variable is not undefined.
*/
toBeDefined(): R;
/**
* When you don't care what a value is, you just want to
* ensure a value is false in a boolean context.
*/
toBeFalsy(): R;
/**
* For comparing floating point numbers.
*/
toBeGreaterThan(expected: number | bigint): R;
/**
* For comparing floating point numbers.
*/
toBeGreaterThanOrEqual(expected: number | bigint): R;
/**
* Ensure that an object is an instance of a class.
* This matcher uses `instanceof` underneath.
*/
toBeInstanceOf(expected: unknown): R;
/**
* For comparing floating point numbers.
*/
toBeLessThan(expected: number | bigint): R;
/**
* For comparing floating point numbers.
*/
toBeLessThanOrEqual(expected: number | bigint): R;
/**
* Used to check that a variable is NaN.
*/
toBeNaN(): R;
/**
* This is the same as `.toBe(null)` but the error messages are a bit nicer.
* So use `.toBeNull()` when you want to check that something is null.
*/
toBeNull(): R;
/**
* Use when you don't care what a value is, you just want to ensure a value
* is true in a boolean context. In JavaScript, there are six falsy values:
* `false`, `0`, `''`, `null`, `undefined`, and `NaN`. Everything else is truthy.
*/
toBeTruthy(): R;
/**
* Used to check that a variable is undefined.
*/
toBeUndefined(): R;
/**
* Used when you want to check that an item is in a list.
* For testing the items in the list, this uses `===`, a strict equality check.
*/
toContain(expected: unknown): R;
/**
* Used when you want to check that an item is in a list.
* For testing the items in the list, this matcher recursively checks the
* equality of all fields, rather than checking for object identity.
*/
toContainEqual(expected: unknown): R;
/**
* Used when you want to check that two objects have the same value.
* This matcher recursively checks the equality of all fields, rather than checking for object identity.
*/
toEqual(expected: unknown): R;
/**
* Ensures that a mock function is called.
*/
toHaveBeenCalled(): R;
/**
* Ensures that a mock function is called an exact number of times.
*/
toHaveBeenCalledTimes(expected: number): R;
/**
* Ensure that a mock function is called with specific arguments.
*/
toHaveBeenCalledWith(...expected: MockParameters<T>): R;
/**
* Ensure that a mock function is called with specific arguments on an Nth call.
*/
toHaveBeenNthCalledWith(nth: number, ...expected: MockParameters<T>): R;
/**
* If you have a mock function, you can use `.toHaveBeenLastCalledWith`
* to test what arguments it was last called with.
*/
toHaveBeenLastCalledWith(...expected: MockParameters<T>): R;
/**
* Use to test the specific value that a mock function last returned.
* If the last call to the mock function threw an error, then this matcher will fail
* no matter what value you provided as the expected return value.
*/
toHaveLastReturnedWith(expected?: unknown): R;
/**
* Used to check that an object has a `.length` property
* and it is set to a certain numeric value.
*/
toHaveLength(expected: number): R;
/**
* Use to test the specific value that a mock function returned for the nth call.
* If the nth call to the mock function threw an error, then this matcher will fail
* no matter what value you provided as the expected return value.
*/
toHaveNthReturnedWith(nth: number, expected?: unknown): R;
/**
* Use to check if property at provided reference keyPath exists for an object.
* For checking deeply nested properties in an object you may use dot notation or an array containing
* the keyPath for deep references.
*
* Optionally, you can provide a value to check if it's equal to the value present at keyPath
* on the target object. This matcher uses 'deep equality' (like `toEqual()`) and recursively checks
* the equality of all fields.
*
* @example
*
* expect(houseForSale).toHaveProperty('kitchen.area', 20);
*/
toHaveProperty(expectedPath: string | Array<string>, expectedValue?: unknown): R;
/**
* Use to test that the mock function successfully returned (i.e., did not throw an error) at least one time
*/
toHaveReturned(): R;
/**
* Use to ensure that a mock function returned successfully (i.e., did not throw an error) an exact number of times.
* Any calls to the mock function that throw an error are not counted toward the number of times the function returned.
*/
toHaveReturnedTimes(expected: number): R;
/**
* Use to ensure that a mock function returned a specific value.
*/
toHaveReturnedWith(expected?: unknown): R;
/**
* Check that a string matches a regular expression.
*/
toMatch(expected: string | RegExp): R;
/**
* Used to check that a JavaScript object matches a subset of the properties of an object
*/
toMatchObject(expected: Record<string, unknown> | Array<Record<string, unknown>>): R;
/**
* Use to test that objects have the same types as well as structure.
*/
toStrictEqual(expected: unknown): R;
/**
* Used to test that a function throws when it is called.
*/
toThrow(expected?: unknown): R;
}
/**
* Obtains the parameters of the given function or {@link MockInstance}'s function type.
* ```ts
* type P = MockParameters<MockInstance<(foo: number) => void>>;
* // or without an explicit mock
* // type P = MockParameters<(foo: number) => void>;
*
* const params1: P = [1]; // compiles
* const params2: P = ['bar']; // error
* const params3: P = []; // error
* ```
*
* This is similar to {@link Parameters}, with these notable differences:
*
* 1. Each of the parameters can also accept an {@link AsymmetricMatcher}.
* ```ts
* const params4: P = [expect.anything()]; // compiles
* ```
* This works with nested types as well:
* ```ts
* type Nested = MockParameters<MockInstance<(foo: { a: number }, bar: [string]) => void>>;
*
* const params1: Nested = [{ foo: { a: 1 }}, ['value']]; // compiles
* const params2: Nested = [expect.anything(), expect.anything()]; // compiles
* const params3: Nested = [{ foo: { a: expect.anything() }}, [expect.anything()]]; // compiles
* ```
*
* 2. This type works with overloaded functions (up to 15 overloads):
* ```ts
* function overloaded(): void;
* function overloaded(foo: number): void;
* function overloaded(foo: number, bar: string): void;
* function overloaded(foo?: number, bar?: string): void {}
*
* type Overloaded = MockParameters<MockInstance<typeof overloaded>>;
*
* const params1: Overloaded = []; // compiles
* const params2: Overloaded = [1]; // compiles
* const params3: Overloaded = [1, 'value']; // compiles
* const params4: Overloaded = ['value']; // error
* const params5: Overloaded = ['value', 1]; // error
* ```
*
* Mocks generated with the default `MockInstance` type will evaluate to `Array<unknown>`:
* ```ts
* MockParameters<MockInstance> // Array<unknown>
* ```
*
* If the given type is not a `MockInstance` nor a function, this type will evaluate to `Array<unknown>`:
* ```ts
* MockParameters<boolean> // Array<unknown>
* ```
*/
type MockParameters<M> = M extends MockInstance<infer F> ? FunctionParameters<F> : FunctionParameters<M>;
/**
* A wrapper over `FunctionParametersInternal` which converts `never` evaluations to `Array<unknown>`.
*
* This is only necessary for Typescript versions prior to 5.3.
*
* In those versions, a function without parameters (`() => any`) is interpreted the same as an overloaded function,
* causing `FunctionParametersInternal` to evaluate it to `[] | Array<unknown>`, which is incorrect.
*
* The workaround is to "catch" this edge-case in `WithAsymmetricMatchers` and interpret it as `never`.
* However, this also affects {@link UnknownFunction} (the default generic type of `MockInstance`):
* ```ts
* FunctionParametersInternal<() => any> // [] | never --> [] --> correct
* FunctionParametersInternal<UnknownFunction> // never --> incorrect
* ```
* An empty array is the expected type for a function without parameters,
* so all that's left is converting `never` to `Array<unknown>` for the case of `UnknownFunction`,
* as it needs to accept _any_ combination of parameters.
*/
type FunctionParameters<F> = FunctionParametersInternal<F> extends never ? Array<unknown> : FunctionParametersInternal<F>;
/**
* 1. If the function is overloaded or has no parameters -> overloaded form (union of tuples).
* 2. If the function has parameters -> simple form.
* 3. else -> `never`.
*/
type FunctionParametersInternal<F> = F extends {
(...args: infer P1): any;
(...args: infer P2): any;
(...args: infer P3): any;
(...args: infer P4): any;
(...args: infer P5): any;
(...args: infer P6): any;
(...args: infer P7): any;
(...args: infer P8): any;
(...args: infer P9): any;
(...args: infer P10): any;
(...args: infer P11): any;
(...args: infer P12): any;
(...args: infer P13): any;
(...args: infer P14): any;
(...args: infer P15): any;
} ? WithAsymmetricMatchers<P1> | WithAsymmetricMatchers<P2> | WithAsymmetricMatchers<P3> | WithAsymmetricMatchers<P4> | WithAsymmetricMatchers<P5> | WithAsymmetricMatchers<P6> | WithAsymmetricMatchers<P7> | WithAsymmetricMatchers<P8> | WithAsymmetricMatchers<P9> | WithAsymmetricMatchers<P10> | WithAsymmetricMatchers<P11> | WithAsymmetricMatchers<P12> | WithAsymmetricMatchers<P13> | WithAsymmetricMatchers<P14> | WithAsymmetricMatchers<P15> : F extends ((...args: infer P) => any) ? WithAsymmetricMatchers<P> : never;
/**
* @see FunctionParameters
*/
type WithAsymmetricMatchers<P extends Array<any>> = Array<unknown> extends P ? never : { [K in keyof P]: DeepAsymmetricMatcher<P[K]> };
/**
* Replaces `T` with `T | AsymmetricMatcher`.
*
* If `T` is an object or an array, recursively replaces all nested types with the same logic:
* ```ts
* type DeepAsymmetricMatcher<boolean>; // AsymmetricMatcher | boolean
* type DeepAsymmetricMatcher<{ foo: number }>; // AsymmetricMatcher | { foo: AsymmetricMatcher | number }
* type DeepAsymmetricMatcher<[string]>; // AsymmetricMatcher | [AsymmetricMatcher | string]
* ```
*/
type DeepAsymmetricMatcher<T> = T extends object ? AsymmetricMatcher$1 | { [K in keyof T]: DeepAsymmetricMatcher<T[K]> } : AsymmetricMatcher$1 | T;
//#endregion
//#region src/asymmetricMatchers.d.ts
declare abstract class AsymmetricMatcher<T> implements AsymmetricMatcher$1 {
protected sample: T;
protected inverse: boolean;
$$typeof: symbol;
constructor(sample: T, inverse?: boolean);
protected getMatcherContext(): MatcherContext;
abstract asymmetricMatch(other: unknown): boolean;
abstract toString(): string;
getExpectedType?(): string;
toAsymmetricMatcher?(): string;
}
//#endregion
//#region src/index.d.ts
declare class JestAssertionError extends Error {
matcherResult?: Omit<SyncExpectationResult, 'message'> & {
message: string;
};
}
declare const expect: Expect;
//#endregion
export { AsymmetricMatcher, AsymmetricMatchers, AsyncExpectationResult, BaseExpect, Expect, ExpectationResult, JestAssertionError, MatcherContext, MatcherFunction, MatcherFunctionWithContext, MatcherState, MatcherUtils, Matchers, SyncExpectationResult, Tester, TesterContext, expect as default, expect };