Type

Sets the Content-Type HTTP header to the MIME type listed here specified by the file extension.

c.Type(t string) string

app.Get("/", func(c *fiber.Ctx) {
  c.Type(".html") // => "text/html"
  c.Type("html")  // => "text/html"
  c.Type("json")  // => "application/json"
  c.Type("png")   // => "image/png"
})