How does nodejs access/return /index.html

  node.js, question

I met the express.static () method, but I don’t know how it works.

One of the questions I think about is, when visiting a website, such as www.test.com, how did he change the url to www.test.com/index.html?

Give me what I think of the code (a general framework only)

app.get('/',function(req,res) {
 //How do I change the url to visit www.test.com/index.html?
 //this problem should not be solved by express.static ()?
 });

The default index.html, otherwise why do you think the homepage is named this? express seems to be one of its own web servers, silently accessing index