After researching service workers a bit, none of the tutorials seem to explicitly state what self actuall is. It's a ServiceWorkerGlobalScope implementation. The events passed to the install and activate listeners are ExtenableEvent implementations. This is where the waitUntil method comes from to force an event listener to wait until a promise resolves. The install… Continue reading What is Self in a Service Worker?
There are broad scenarios in which a single page app (SPA) needs to handle authentication: The SPA is using an API custom built for the app itself -- the API being used is not public in any other way The SPA is using an API built for public consumption -- one with a full fledged… Continue reading Handling Authentication Tokens in Single Page Apps
Common advice in languages with exceptions is that exceptions are not for control flow. A rejected promise is not any different than a thrown exception: in both cases something when exceptionally wrong and must be dealt with. This week I was fighting with promises while building a slack app because I was attempting to use… Continue reading Promises are Not for Control Flow
One of the things I enjoy about ECMAScript modules is their ease on the eyes. They look good -- the same way Python's import statement can look nice. It's also nice to have to explicitly import the things necessary for a file/module to its work. Need the whole module? That's a choice that has to… Continue reading Beautiful Imports in NodeJS
One of the things I try to do when building applications is keep servers stateless. This makes those servers easy to throw away -- a piece of infrastructure failing (which it always will) is not a big deal with stateless servers. Just spin up a new one. When the requirement came down the pipeline to… Continue reading Building an Upload System Backed by S3 and Client-Side Uploads
Showing a user something like a progress bar during a file upload is handy and let's them know that stuff is working. Higher level abstractions like fetch don't really provide a look into how much of a request body has been sent, but good ol' XMLHttpRequest does. In order to monitor upload progress, attach an… Continue reading How to Monitor Client-Side Upload Progress (with XMLHttpRequest)