feat(router): add support for relative paths (#14)

Closes #2, #17

libs/angular-routing/src/lib/router.service.ts

@@ -47,6 +47,10 @@ export class Router {
   }
 
   serializeUrl(url: string, queryParams?: Params, hash?: string) {
+    // if relative path
+    if (!url.startsWith('/')) {
+      url = this.urlParser.joinUrls(this.location.path(), url);
+    }
     return (
       url +
       (queryParams ? `?${queryString.stringify(queryParams)}` : '') +
@@ -70,7 +74,7 @@ export class Router {
   }
 
   parseSearchParams(searchParams: URLSearchParams) {
-    let queryParams: Params = {};
+    const queryParams: Params = {};
 
     searchParams.forEach((value, key) => {
       queryParams[key] = value;

libs/angular-routing/src/lib/url-parser.spec.ts

@@ -0,0 +1,32 @@
+import { UrlParser } from 'angular-routing';
+
+describe('UrlParser', () => {
+  let parser: UrlParser;
+
+  beforeEach(() => {
+    parser = new UrlParser();
+  });
+
+  describe('joinUrls', () => {
+    it('should join two urls', () => {
+      expect(parser.joinUrls('path1/path2', 'path3/path4'))
+        .toEqual('path1/path2/path3/path4');
+    });
+    it('should strip off original query params', () => {
+      expect(parser.joinUrls('path1/path2?param1=value1', 'path3/path4'))
+        .toEqual('path1/path2/path3/path4');
+    });
+    it('should leave query params on target url', () => {
+      expect(parser.joinUrls('path1/path2', 'path3/path4?param1=value1'))
+        .toEqual('path1/path2/path3/path4?param1=value1');
+    });
+    it('should ignore cwd on segment', () => {
+      expect(parser.joinUrls('path1/path2', './path3/path4?param1=value1'))
+        .toEqual('path1/path2/path3/path4?param1=value1');
+    });
+    it('should apply ".." to go back through segments', () => {
+      expect(parser.joinUrls('path1/path2', '../../path3/path4?param1=value1'))
+        .toEqual('path3/path4?param1=value1');
+    });
+  });
+});

libs/angular-routing/src/lib/url-parser.ts

@@ -5,4 +5,24 @@ export class UrlParser {
   parse(url: string, base?: string | URL): URL {
     return new URL(url, base);
   }
+
+  joinUrls(currentUrl: string, url: string): string {
+    const currentUrlSegments = currentUrl
+      .split('#')[0] // remove hash
+      .split('?')[0] // remove query params
+      .split('/');
+    const urlSegments = url.split('/');
+
+    return urlSegments
+      .reduce((segments, segment) => {
+        if (segment === '.') {
+          return segments;
+        }
+        if (segment === '..') {
+          return segments.slice(0, -1);
+        }
+        return [...segments, segment];
+      }, currentUrlSegments)
+      .join('/');
+  }
 }