I am new to programming which makes things slightly difficult for me to understand if I read the official docs.
I was reading about React Router 4 from here
In this article, the author was talking about <HashRouter> and <BrowserRouter>
This is what he mentioned:
HashRouter basically it uses the hash in the URL to render the component. Since I was building a static one-page website, I needed to use this.
BrowserRouter, it uses HTML5 history API to render the component. The history can be modified via pushState and replaceState. More information can be found here
Now, I don't get the significance and use cases for both, Like what does he mean when he says history can be modified via pushState and replaceState and it uses the hash in the URL to render the component
While the first explanation for BrowserRouter is entirely vague to me, the second explanation about HashRouter also doesn't make sense, like why would someone use Hash (#) in the url to render the component?
BrowserRouterIt uses history API, i.e. it's unavailable for legacy browsers (IE 9 and lower and contemporaries). Client-side React application is able to maintain clean routes like example.com/react/route but needs to be backed by web server. Usually this means that web server should be configured for single-page application, i.e. same index.html is served for /react/route path or any other route on server side. On client side, window.location.pathname is parsed by React router. React router renders a component that it was configured to render for /react/route.
Additionally, the setup may involve server-side rendering, index.html may contain rendered components or data that are specific to current route.
HashRouterIt uses URL hash, it puts no limitations on supported browsers or web server. Server-side routing is independent from client-side routing.
Backward-compatible single-page application can use it as example.com/#/react/route. The setup cannot be backed up by server-side rendering because it's / path that is served on server side, #/react/route URL hash cannot be read from server side. On client side, window.location.hash is parsed by React router. React router renders a component that it was configured to render for /react/route, similarly to BrowserRouter.
Most importantly, HashRouter use cases aren't limited to SPA. A website may have legacy or search engine-friendly server-side routing, while React application may be a widget that maintains its state in URL like example.com/server/side/route#/react/route. Some page that contains React application is served on server side for /server/side/route, then on client side React router renders a component that it was configured to render for /react/route, similarly to previous scenario.
SERVER SIDE: HashRouter uses a hash symbol in the URL, which has the effect of all subsequent URL path content being ignored in the server request (ie you send "www.mywebsite.com/#/person/john" the server gets "www.mywebsite.com". As a result the server will return the pre # URL response, and then the post # path will be handled (or parsed) by your client side react application.
CLIENT SIDE: BrowserRouter will not append the # symbol to your URL, however will create issues when you try to link to a page or reload a page. If the explicit route exists in your client react app, but not on your server, reloading and linking(anything that hits the server directly) will return 404 not found errors.
Refreshing the page causes the browser to send a GET request to the server using the current route. The # was used to prevent us from sending that GET request. We use the BrowserRouter because we want the GET request to be sent to the server. In order to render the router on the server, we need a location — we need the route. This route will be used on the server to tell the router what to render. The BrowserRouter is used when you want to render routes isomorphically.