posted in Angular 

It's very easy to make a mistake on Angular2 router. After refresh the page, the page to be routed to can not load successfully. Chrome console tell me that browser failed to load css resources as the path of resources is incorrect.

The solution is that put the <base href="/"/> directly under the title tag.

posted in Angular 

When I type npm start in my angular2 project, terminal shows:

Subsequent variable declarations must have the same type. Variable '$' must be of type 'JQueryStatic', but here has type 'cssSelectorHelper'
There is a conflict between angular-protractor and jQuery. One soluction I googled is marked down below:

Modify your jquery.d.ts file
From:

declare module "jquery" {
    export = $;
}
declare var jQuery: JQueryStatic;
declare var $: JQueryStatic;

To:

declare module "jquery" {
    export = jQuery;
}
declare var jQuery: JQueryStatic;

On the contrary, you can change protractor also.
References:
[1] How to use jquery with angular2