fix: adding types to jest matchers

Author: hanseltime

packages/jest/src/index.ts

@@ -5,6 +5,8 @@ import {
 } from 'fetch-mock';
 import './jest-extensions.js';
 import type { Jest } from '@jest/environment';
+import type { FetchMockMatchers } from './types.js';
+export { FetchMockMatchers } from './types.js';
 
 type MockResetOptions = {
 	includeSticky: boolean;
@@ -55,3 +57,17 @@ const fetchMockJest = new FetchMockJest({
 });
 
 export default fetchMockJest;
+
+/* eslint-disable @typescript-eslint/no-namespace */
+/**
+ * Export types on the expect object
+ */
+declare global {
+	namespace jest {
+		// Type-narrow expect for FetchMock
+		interface Expect {
+			(actual: FetchMock): FetchMockMatchers;
+		}
+	}
+}
+/* eslint-enable @typescript-eslint/no-namespace */

packages/jest/src/jest-extensions.ts

@@ -6,7 +6,16 @@ import type {
 	CallHistoryFilter,
 	UserRouteConfig,
 } from 'fetch-mock';
-const methodlessExtensions = {
+import {
+	HumanVerbMethodNames,
+	HumanVerbs,
+	RawFetchMockMatchers,
+} from './types.js';
+
+const methodlessExtensions: Pick<
+	RawFetchMockMatchers,
+	HumanVerbMethodNames<'Fetched'>
+> = {
 	toHaveFetched: (
 		{ fetchMock }: { fetchMock: FetchMock },
 		filter: CallHistoryFilter,
@@ -128,25 +137,24 @@ function scopeExpectationNameToMethod(name: string, humanVerb: string): string {
 	return name.replace('Fetched', humanVerb);
 }
 
-[
-	'Got:get',
-	'Posted:post',
-	'Put:put',
-	'Deleted:delete',
-	'FetchedHead:head',
-	'Patched:patch',
-].forEach((verbs) => {
-	const [humanVerb, method] = verbs.split(':');
+const expectMethodNameToMethodMap: {
+	[humanVerb in Exclude<HumanVerbs, 'Fetched'>]: string;
+} = {
+	Got: 'get',
+	Posted: 'post',
+	Put: 'put',
+	Deleted: 'delete',
+	FetchedHead: 'head',
+	Patched: 'patch',
+};
 
-	const extensions: {
-		// eslint-disable-next-line  @typescript-eslint/no-explicit-any
-		[key: string]: (...args: any[]) => SyncExpectationResult;
-	} = Object.fromEntries(
+Object.entries(expectMethodNameToMethodMap).forEach(([humanVerb, method]) => {
+	const extensions = Object.fromEntries(
 		Object.entries(methodlessExtensions).map(([name, func]) => [
 			scopeExpectationNameToMethod(name, humanVerb),
 			scopeExpectationFunctionToMethod(func, method),
 		]),
-	);
+	) as Omit<RawFetchMockMatchers, HumanVerbMethodNames<'Fetched'>>;
 
 	expect.extend(extensions);
 });

packages/jest/src/types.ts

@@ -0,0 +1,91 @@
+import type { CallHistoryFilter, FetchMock, UserRouteConfig } from 'fetch-mock';
+import type { SyncExpectationResult } from 'expect';
+
+export type HumanVerbs =
+	| 'Got'
+	| 'Posted'
+	| 'Put'
+	| 'Deleted'
+	| 'FetchedHead'
+	| 'Patched'
+	| 'Fetched';
+
+/**
+ * Verify that a particular call for the HTTP method implied in the function name
+ * has occurred
+ */
+export type ToHaveFunc = (
+	filter: CallHistoryFilter,
+	options: UserRouteConfig,
+) => SyncExpectationResult;
+
+/**
+ * Verify that a particular Nth call for the HTTP method implied in the function name
+ * has occurred
+ */
+export type ToHaveNthFunc = (
+	n: number,
+	filter: CallHistoryFilter,
+	options: UserRouteConfig,
+) => SyncExpectationResult;
+
+/**
+ * Verify that a particular call for the HTTP method implied in the function name
+ * has been made N times
+ */
+export type ToHaveTimesFunc = (
+	times: number,
+	filter: CallHistoryFilter,
+	options: UserRouteConfig,
+) => SyncExpectationResult;
+
+export type FetchMockMatchers = {
+	toHaveFetched: ToHaveFunc;
+	toHaveLastFetched: ToHaveFunc;
+	toHaveFetchedTimes: ToHaveTimesFunc;
+	toHaveNthFetched: ToHaveNthFunc;
+	toHaveGot: ToHaveFunc;
+	toHaveLastGot: ToHaveFunc;
+	toHaveGotTimes: ToHaveTimesFunc;
+	toHaveNthGot: ToHaveNthFunc;
+	toHavePosted: ToHaveFunc;
+	toHaveLastPosted: ToHaveFunc;
+	toHavePostedTimes: ToHaveTimesFunc;
+	toHaveNthPosted: ToHaveNthFunc;
+	toHavePut: ToHaveFunc;
+	toHaveLastPut: ToHaveFunc;
+	toHavePutTimes: ToHaveTimesFunc;
+	toHaveNthPut: ToHaveNthFunc;
+	toHaveDeleted: ToHaveFunc;
+	toHaveLastDeleted: ToHaveFunc;
+	toHaveDeletedTimes: ToHaveTimesFunc;
+	toHaveNthDeleted: ToHaveNthFunc;
+	toHaveFetchedHead: ToHaveFunc;
+	toHaveLastFetchedHead: ToHaveFunc;
+	toHaveFetchedHeadTimes: ToHaveTimesFunc;
+	toHaveNthFetchedHead: ToHaveNthFunc;
+	toHavePatched: ToHaveFunc;
+	toHaveLastPatched: ToHaveFunc;
+	toHavePatchedTimes: ToHaveTimesFunc;
+	toHaveNthPatched: ToHaveNthFunc;
+};
+
+// types for use doing some intermediate type checking in extensions to make sure things don't get out of sync
+/**
+ * This type allows us to take the Matcher type and creat another one
+ */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+type RawMatcher<T extends (...args: any[]) => any> = (
+	input: { fetchMock: FetchMock },
+	...args: Parameters<T>
+) => ReturnType<T>;
+
+export type RawFetchMockMatchers = {
+	[k in keyof FetchMockMatchers]: RawMatcher<FetchMockMatchers[k]>;
+};
+
+export type HumanVerbMethodNames<M extends HumanVerbs> =
+	| `toHave${M}`
+	| `toHaveLast${M}`
+	| `toHave${M}Times`
+	| `toHaveNth${M}`;