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sw.js
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sw.js
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const preLoad = function() {
return caches.open("offline").then(function(cache) {
// caching index and important routes
return cache.addAll(filesToCache);
});
};
self.addEventListener("install", function(event) {
event.waitUntil(preLoad());
});
const filesToCache = [
'/offline.html'
];
const checkResponse = function(request) {
return new Promise(function(fulfill, reject) {
fetch(request).then(function(response) {
if (response.status !== 404) {
fulfill(response);
} else {
reject();
}
}, reject);
});
};
const addToCache = function(request) {
return caches.open("offline").then(function(cache) {
return fetch(request).then(function(response) {
return cache.put(request, response);
});
});
};
const returnFromCache = function(request) {
return caches.open("offline").then(function(cache) {
return cache.match(request).then(function(matching) {
if (!matching || matching.status === 404) {
return cache.match("offline.html");
} else {
return matching;
}
});
});
};
self.addEventListener("fetch", function(event) {
event.respondWith(checkResponse(event.request).catch(function() {
return returnFromCache(event.request);
}));
if (!event.request.url.startsWith('http')) {
event.waitUntil(addToCache(event.request));
}
});