fix: inference of paths for typesafeBrowserRouter

.changeset/friendly-pugs-cheat.md

@@ -0,0 +1,5 @@
+---
+"react-router-typesafe": patch
+---
+
+Fixed an issue where mixed paths with children and without would lead to flaky inference of paths

.changeset/loud-feet-live.md

@@ -0,0 +1,5 @@
+---
+"react-router-typesafe": minor
+---
+
+typesafeBrowserRouter now infers correct paths for relative paths

.prettierrc.cjs

@@ -4,4 +4,5 @@ module.exports = {
 	useTabs: true,
 	singleQuote: true,
 	endOfLine: 'auto',
+	experimentalTernaries: true,
 };

.vscode/settings.json

@@ -1,18 +1,18 @@
 {
-  "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": true
-  },
-  "editor.formatOnSave": true,
-  "editor.defaultFormatter": "esbenp.prettier-vscode",
-  "[typescript]": {
-    "typescript.preferences.importModuleSpecifier": "non-relative"
-  },
-  "[typescriptreact]": {
-    "editor.codeActionsOnSave": {
-      "source.organizeImports": true
-    }
-  },
-  "window.commandCenter": true,
-  "editor.rulers": [120],
-  "workbench.tree.indent": 16
+	"editor.codeActionsOnSave": {
+		"source.fixAll.eslint": "explicit"
+	},
+	"editor.formatOnSave": true,
+	"editor.defaultFormatter": "esbenp.prettier-vscode",
+	"[typescript]": {
+		"typescript.preferences.importModuleSpecifier": "non-relative"
+	},
+	"[typescriptreact]": {
+		"editor.codeActionsOnSave": {
+			"source.organizeImports": "explicit"
+		}
+	},
+	"window.commandCenter": true,
+	"editor.rulers": [120],
+	"workbench.tree.indent": 16
 }

package.json

@@ -1,54 +1,54 @@
 {
-	"name": "react-router-typesafe",
-	"version": "1.4.4",
-	"author": "fredericoo",
-	"repository": {
-		"type": "git",
-		"url": "https://github.com/stargaze-co/react-router-typesafe.git"
-	},
-	"scripts": {
-		"build": "tsup",
-		"release": "bun run build && changeset publish"
-	},
-	"main": "./dist/index.js",
-	"module": "./dist/index.mjs",
-	"devDependencies": {
-		"@changesets/cli": "^2.26.2",
-		"@happy-dom/global-registrator": "^11.0.6",
-		"@testing-library/react": "^14.0.0",
-		"bun-types": "^1.0.1",
-		"eslint": "^8.45.0",
-		"expect-type": "^0.16.0",
-		"happy-dom": "^11.0.6",
-		"prettier": "^3.0.0",
-		"react": "^18.2.0",
-		"react-router-dom": "^6.16.0",
-		"tsup": "^7.1.0",
-		"typescript": "^5.1.6"
-	},
-	"peerDependencies": {
-		"react": ">= 17",
-		"react-router-dom": ">= 6.4.0",
-		"typescript": ">= 4.9"
-	},
-	"exports": {
-		".": {
-			"require": "./dist/index.js",
-			"import": "./dist/index.mjs",
-			"types": "./dist/index.d.ts"
-		}
-	},
-	"description": "type safe patches of react-router-dom",
-	"files": [
-		"dist"
-	],
-	"keywords": [
-		"react",
-		"react-router",
-		"react-router-dom",
-		"remix",
-		"remix-router"
-	],
-	"license": "ISC",
-	"types": "./dist/index.d.ts"
+  "name": "react-router-typesafe",
+  "version": "1.4.4",
+  "author": "fredericoo",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/stargaze-co/react-router-typesafe.git"
+  },
+  "scripts": {
+    "build": "tsup",
+    "release": "bun run build && changeset publish"
+  },
+  "main": "./dist/index.js",
+  "module": "./dist/index.mjs",
+  "devDependencies": {
+    "@changesets/cli": "^2.26.2",
+    "@happy-dom/global-registrator": "^11.0.6",
+    "@testing-library/react": "^14.0.0",
+    "bun-types": "^1.0.1",
+    "eslint": "^8.45.0",
+    "expect-type": "^0.16.0",
+    "happy-dom": "^11.0.6",
+    "prettier": "^3.2.5",
+    "react": "^18.2.0",
+    "react-router-dom": "^6.16.0",
+    "tsup": "^7.1.0",
+    "typescript": "^5.1.6"
+  },
+  "peerDependencies": {
+    "react": ">= 17",
+    "react-router-dom": ">= 6.4.0",
+    "typescript": ">= 4.9"
+  },
+  "exports": {
+    ".": {
+      "require": "./dist/index.js",
+      "import": "./dist/index.mjs",
+      "types": "./dist/index.d.ts"
+    }
+  },
+  "description": "type safe patches of react-router-dom",
+  "files": [
+    "dist"
+  ],
+  "keywords": [
+    "react",
+    "react-router",
+    "react-router-dom",
+    "remix",
+    "remix-router"
+  ],
+  "license": "ISC",
+  "types": "./dist/index.d.ts"
 }

src/__tests__/browser-router.test.ts

@@ -1,12 +1,15 @@
 import { test, expect } from 'bun:test';
 import { typesafeBrowserRouter } from '../browser-router';
+import { RouteObject } from 'react-router-dom';
 
 test('returns pathname with replaced params', () => {
 	const { href } = typesafeBrowserRouter([
 		{ path: '/blog', children: [{ path: '/blog/:postId', children: [{ path: '/blog/:postId/:commentId' }] }] },
 	]);
 
 	const output = href({ path: '/blog/:postId/:commentId', params: { postId: 'foo', commentId: 'bar' } });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog/foo/bar');
 });
@@ -28,6 +31,8 @@ test('Returns right paths with pathless routes with children', () => {
 	]);
 
 	const output = href({ path: '/blog/:postId/:commentId', params: { postId: 'foo', commentId: 'bar' } });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog/foo/bar');
 });
@@ -36,6 +41,8 @@ test('returns pathname with search params if object is passed', () => {
 	const { href } = typesafeBrowserRouter([{ path: '/blog', children: [{ path: '/blog/:postId' }] }]);
 
 	const output = href({ path: '/blog/:postId', params: { postId: 'foo' }, searchParams: { foo: 'bar' } });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog/foo?foo=bar');
 });
@@ -48,6 +55,8 @@ test('returns pathname with search params if URLSearchParams is passed', () => {
 		params: { postId: 'foo' },
 		searchParams: new URLSearchParams({ foo: 'bar' }),
 	});
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog/foo?foo=bar');
 });
@@ -56,6 +65,8 @@ test('returns pathname with hash', () => {
 	const { href } = typesafeBrowserRouter([{ path: '/blog', children: [{ path: '/blog/:postId' }] }]);
 
 	const output = href({ path: '/blog/:postId', params: { postId: 'foo' }, hash: '#foo' });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog/foo#foo');
 });
@@ -157,6 +168,69 @@ test('typescript stress test with many routes and layers', () => {
 	]);
 
 	const output = href({ path: '/blog' });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
 
 	expect(output).toEqual('/blog');
 });
+
+test('works with pathless routes', () => {
+	const grandChildren = [{ element: null }, { path: '/blog/:postId/comments' }] as const satisfies RouteObject[];
+	const children = [{ children: grandChildren }] as const satisfies RouteObject[];
+
+	const { href } = typesafeBrowserRouter([{ path: '/blog', children }]);
+
+	const output = href({ path: '/blog/:postId/comments', params: { postId: 'asd' } });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
+
+	expect(output).toEqual('/blog/asd/comments');
+});
+
+test('can reference groups of routes by variable on several layers', () => {
+	const appRoutes = [
+		{
+			index: true,
+			element: null,
+		},
+		{
+			path: '/app/contact',
+			element: null,
+		},
+	] as const satisfies RouteObject[];
+
+	const { href } = typesafeBrowserRouter([
+		{
+			path: '/',
+			children: [
+				{
+					index: true,
+					element: null,
+				},
+				{
+					path: '/app',
+					element: null,
+					children: appRoutes,
+				},
+			],
+		},
+	]);
+
+	const output = href({ path: '/app/contact' });
+	// @ts-expect-error
+	const wrongOutput = href({ path: 'non-existing-route' });
+
+	expect(output).toEqual('/app/contact');
+});
+
+test('works with relative paths', () => {
+	const { href } = typesafeBrowserRouter([
+		{ path: '/', children: [{ path: 'blog', children: [{ path: ':postId', children: [{ path: 'comments' }] }] }] },
+	]);
+
+	const output = href({ path: '/blog/:postId/comments', params: { postId: 'asd' } });
+	// @ts-expect-error
+	const wrongOutput = href({ path: '/comments' });
+
+	expect(output).toEqual('/blog/asd/comments');
+});

src/browser-router.ts

@@ -13,19 +13,25 @@ type PathParams<T> = keyof T extends never ? { params?: never } : { params: T };
 
 type ExtractParam<Path, NextPart> = Path extends `:${infer Param}` ? Record<Param, string> & NextPart : NextPart;
 
-type ExtractParams<Path> = Path extends `${infer Segment}/${infer Rest}`
-	? ExtractParam<Segment, ExtractParams<Rest>>
-	: ExtractParam<Path, {}>;
+type ExtractParams<Path> =
+	Path extends `${infer Segment}/${infer Rest}` ? ExtractParam<Segment, ExtractParams<Rest>> : ExtractParam<Path, {}>;
 
-type ExtractPaths<Route extends RouteObject> = Route extends {
-	children: infer C extends RouteObject[];
-	path: infer P extends string;
-}
-	? P | ExtractPaths<C[number]>
-	: Route extends { children: infer C extends RouteObject[] }
-	? ExtractPaths<C[number]>
-	: Route extends { path: infer P extends string }
-	? P
+type PrefixIfRelative<Path extends string, Prefix extends string> =
+	Path extends `/${string}` ? Path
+	: Prefix extends '' ? `/${Path}`
+	: Prefix extends '/' ? `${Prefix}${Path}`
+	: `${Prefix}/${Path}`;
+
+type ExtractPaths<Route extends RouteObject, Prefix extends string> =
+	Route extends (
+		{
+			children: infer C extends RouteObject[];
+			path: infer P extends string;
+		}
+	) ?
+		PrefixIfRelative<P, Prefix> | ExtractPaths<C[number], PrefixIfRelative<P, Prefix>>
+	: Route extends { children: infer C extends RouteObject[] } ? ExtractPaths<C[number], Prefix>
+	: Route extends { path: infer P extends string } ? PrefixIfRelative<P, Prefix>
 	: never;
 
 type TypesafeSearchParams = Record<string, string> | URLSearchParams;
@@ -36,20 +42,21 @@ const joinValidWith =
 	(...valid: any[]) =>
 		valid.filter(Boolean).join(separator);
 
-export const typesafeBrowserRouter = <R extends RouteObject>(routes: NarrowArray<R>) => {
-	type Paths = ExtractPaths<R>;
+export const typesafeBrowserRouter = <const R extends RouteObject>(routes: NarrowArray<R>) => {
+	type Paths = ExtractPaths<R, ''>;
 
 	function href<P extends Paths>(
 		params: { path: Extract<P, string> } & PathParams<Flatten<ExtractParams<P>>> & RouteExtraParams,
 	) {
 		// applies all params to the path
-		const path = params?.params
-			? Object.keys(params.params).reduce((path, param) => {
+		const path =
+			params?.params ?
+				Object.keys(params.params).reduce((path, param) => {
 					const value = params.params![param as keyof ExtractParams<P>];
 					if (typeof value !== 'string') throw new Error(`Route param ${param} must be a string`);
 					return path.replace(`:${param}`, value);
-			  }, params.path)
-			: params.path;
+				}, params.path)
+			:	params.path;
 
 		const searchParams = new URLSearchParams(params?.searchParams);
 		const hash = params?.hash?.replace(/^#/, '');