feat: add inject function

Author: lukeed

index.d.ts

@@ -7,3 +7,16 @@ export function parse(route: RegExp): {
 	keys: false;
 	pattern: RegExp;
 }
+
+export type RouteParams<T extends string> =
+	T extends `${string}:${infer P}?/${infer Rest}`
+		? { [K in P]?: string } & RouteParams<Rest>
+	: T extends `${string}:${infer P}/${infer Rest}`
+		? { [K in P]: string } & RouteParams<Rest>
+	: T extends `${string}:${infer P}?`
+		? { [K in P]?: string }
+	: T extends `${string}:${infer P}`
+		? { [K in P]: string }
+	: {};
+
+export function inject<T extends string>(route: T, values: RouteParams<T>): string;

src/index.js

@@ -24,3 +24,13 @@ export function parse(str, loose) {
 		pattern: new RegExp('^' + pattern + (loose ? '(?=$|\/)' : '\/?$'), 'i')
 	};
 }
+
+var RGX = /*#__PURE__*/ /(\/|^)([:*][^\/]*?)(\?)?(?=[\/.]|$)/g;
+
+// error if key missing?
+export function inject(route, values) {
+	return route.replace(RGX, (_, start, key, optional) => {
+		if (_ = values[key.substring(1)]) return '/' + _;
+		return optional ? '' : '/' + key;
+	});
+}

test/inject.js

@@ -0,0 +1,75 @@
+import { test } from 'uvu';
+import * as assert from 'uvu/assert';
+import { inject } from '../src';
+
+/**
+ * @param {string} pattern
+ * @param {string} expected
+ * @param {Record<string, any>} values
+ */
+function run(pattern, expected, values) {
+	let keys = Object.keys(values);
+	test(`inject "${pattern}" with [${keys}]`, () => {
+		let output = inject(pattern, values);
+		assert.type(output, 'string');
+		assert.is(output, expected);
+	});
+}
+
+test('exports', () => {
+	assert.type(inject, 'function');
+});
+
+test('returns', () => {
+	let output = inject('/', {});
+	assert.type(output, 'string');
+});
+
+test('throws', () => {
+	try {
+		inject('/:foo/:bar');
+		assert.unreachable('should throw');
+	} catch (err) {
+		assert.instance(err, TypeError);
+		assert.is(err.message, `Cannot read property 'foo' of undefined`);
+	}
+});
+
+// Test Outputs
+// ---
+
+run('/foo/:id', '/foo/123', { id: 123 });
+run('/foo/:id/', '/foo/123/', { id: 123 });
+
+run('/:a/:b/:c', '/1/2/3', { a: 1, b: 2, c: 3 });
+run('/:a/:b/:c/', '/1/2/3/', { a: 1, b: 2, c: 3 });
+
+run('/assets/:video.mp4', '/assets/demo.mp4', { video: 'demo' });
+run('/assets/:video.mp4/extra', '/assets/demo.mp4/extra', { video: 'demo' });
+run('/assets/:video.mp4?foo=bar', '/assets/demo.mp4?foo=bar', { video: 'demo' });
+run('/assets/:video/.hidden', '/assets/demo/.hidden', { video: 'demo' });
+
+run('/foo/:id/:bar?', '/foo/123', { id: 123 });
+run('/foo/:id/:bar?/', '/foo/123/', { id: 123 });
+
+run('/foo/:id/:bar?', '/foo/123/xxx', { id: 123, bar: 'xxx' });
+run('/foo/:id/:bar?/', '/foo/123/xxx/', { id: 123, bar: 'xxx' });
+
+run('/foo/:id/:bar?/extra', '/foo/123/extra', { id: 123 });
+run('/foo/:id/:bar?/extra', '/foo/123/xxx/extra', { id: 123, bar: 'xxx' });
+
+run('/foo/:id/:a?/:b?/:bar?', '/foo/123', { id: 123 });
+run('/foo/:id/:a?/:b?/:bar?', '/foo/123/bb', { id: 123, b: 'bb' });
+run('/foo/:id/:a?/:b?/:bar?', '/foo/123/xxx', { id: 123, bar: 'xxx' });
+run('/foo/:id/:a?/:b?/:bar?', '/foo/123/aa/xxx', { id: 123, a: 'aa', bar: 'xxx' });
+
+
+// NOTE: Missing non-optional values
+// ---
+run('/foo/:id', '/foo/:id', { /* empty */ });
+run('/foo/:id/', '/foo/:id/', { /* empty */ });
+
+run('/:a/:b/:c', '/1/:b/:c', { a: 1 });
+run('/:a/:b/:c', '/1/:b/3', { a: 1, c: 3 });
+
+test.run();