fix(router): redirect should not add unnecessary brackets

modules/@angular/router/src/apply_redirects.ts

@@ -235,19 +235,28 @@ function split(
     const s = new UrlSegment(
         consumedPaths,
         createChildrenForEmptyPaths(config, new UrlSegment(slicedPath, segment.children)));
-    return {segment: s, slicedPath: []};
+    return {segment: mergeTrivialChildren(s), slicedPath: []};
 
   } else if (slicedPath.length === 0 && containsEmptyPathRedirects(segment, slicedPath, config)) {
     const s = new UrlSegment(
         segment.pathsWithParams,
         addEmptyPathsToChildrenIfNeeded(segment, slicedPath, config, segment.children));
-    return {segment: s, slicedPath};
+    return {segment: mergeTrivialChildren(s), slicedPath};
 
   } else {
     return {segment, slicedPath};
   }
 }
 
+function mergeTrivialChildren(s: UrlSegment): UrlSegment {
+  if (s.numberOfChildren === 1 && s.children[PRIMARY_OUTLET]) {
+    const c = s.children[PRIMARY_OUTLET];
+    return new UrlSegment(s.pathsWithParams.concat(c.pathsWithParams), c.children);
+  } else {
+    return s;
+  }
+}
+
 function addEmptyPathsToChildrenIfNeeded(
     segment: UrlSegment, slicedPath: UrlPathWithParams[], routes: Route[],
     children: {[name: string]: UrlSegment}): {[name: string]: UrlSegment} {

modules/@angular/router/src/url_tree.ts

@@ -96,7 +96,15 @@ export class UrlSegment {
     forEach(children, (v: any, k: any) => v.parent = this);
   }
 
-  hasChildren(): boolean { return Object.keys(this.children).length > 0; }
+  /**
+   * Return true if the segment has child segments
+   */
+  hasChildren(): boolean { return this.numberOfChildren > 0; }
+
+  /**
+   * Returns the number of child sements.
+   */
+  get numberOfChildren(): number { return Object.keys(this.children).length; }
 
   toString(): string { return serializePaths(this); }
 }