index.js for service worker hijacking requests 1, 2, and 3

The code below responds with a Dr Evil GIF no matter what:

self.addEventListener('fetch', function(event) {
  event.respondWith(
    fetch('/imgs/dr-evil.gif')
  );
});


The code below only responds with a Dr. Evil GIF where the request ends with .JPG:

self.addEventListener('fetch', function(event) {
  if (event.request.url.endsWith('.jpg')) {
    event.respondWith(
      fetch('/imgs/dr-evil.gif')
    );
  }
});


The code below responds with icon.png where the request ends with .JPG:

self.addEventListener('fetch', function(event) {
  if (event.request.url.endsWith('.jpg')) {
    event.respondWith(
      //fetch('/imgs/dr-evil.gif')
      fetch('/imgs/icon.png')
    );
  }
});


The code below responds with one message when the URL is not found and another message when we completely have no WiFi at all:

self.addEventListener('fetch', function(event) {
    event.respondWith(

    fetch(event.request)

    .then(function(response) {
      if (response.status === 404) {
        // TODO: instead, respond with the gif at
        // /imgs/dr-evil.gif
        // using a network request
        //fetch('/imgs/dr-evil.gif')
        return new Response("Whoops, not found");
      }
      return response;
    })

    .catch(function() {
      return new Response("Uh oh, that totally failed!");
    }) 

  );

});


The code below is the same as the code above except instead of responding with new Response("Whoops, not found") we responds with fetch('/imgs/dr-evil.gif') when the URL is not found and another message when we completely have no WiFi at all:

self.addEventListener('fetch', function(event) {
    event.respondWith(

    fetch(event.request)

    .then(function(response) {
      if (response.status === 404) {
        // TODO: instead, respond with the gif at
        // /imgs/dr-evil.gif
        // using a network request
        //return new Response("Whoops, not found");
        return fetch('/imgs/dr-evil.gif');
      }
      return response;
    })

    .catch(function() {
      return new Response("Uh oh, that totally failed!");
    }) 

  );

});


https://classroom.udacity.com/courses/ud899-gwg/lessons/6381510081/concepts/63885494460923


https://classroom.udacity.com/courses/ud899-gwg/lessons/6381510081/concepts/63885494490923