So you want to write a sync system for a web app with offline and realtime support? Good luck. You might find the following resources useful.
Database in a browser, a spec (Stepan Parunashvili)
What problem are we trying to solve with a sync system?
The web of tomorrow (Nikita Prokopov)
This gist lists challenges you run into when building offline-first applications based on IndexedDB, including open-source libraries like Firebase, pouchdb and AWS amplify (more).
Note that some of the following issues affect only Safari. Out of the major browsers, Chrome's IndexedDB implementation is the best.
When this bug occurs, every time you use the indexeddb, the WAL file grows. Garbage collection doesn't seem to be working, so after a while, you end up with gigabytes of data.
For offline-first operation, browser apps cache data in an IndexedDb database. When the user makes a change while offline, they persist the change optimistically. When connectivity is restored, changes are synced to the server.
This pattern is well established today. However, given the possibility of opening the app in multiple tabs at the same time, we seem to be faced with a dilemma:
We allow users to use the app and to make changes in multiple tabs at the same time. But then two "threads" are writing to the same shared resource at the same time. Co-ordinating writes seems to be difficult.
To make things worse, while the localStorage API allows you to register a callback that fires whenever an item is changed outside the current tab, the IndexedDb API doesn't, at least not in a widely-available way.
This gist collects publications by GeePaw Hill around the topic of Incrementalism in Software Development - the advice to "take many more, much smaller steps." (MMMSS)
The good entry point into the discussion is a pair of 2020 muses: The RAT: Rework Avoidance Theory and Understanding Incremental Switchover
Later muses are also published as podcast episodes.
| import test from "node:test"; | |
| import assert from "node:assert"; | |
| interface IExperiment { | |
| foo(opts: {}): void; | |
| } | |
| class Experiment implements IExperiment { | |
| // Wat?! | |
| // Why is Experiment allowed to implement IExperiment (the typechecker doesn't complain) |
Behavioral questions (aka "Tell me about a time when...")
Tips for Tackling "Tell Me About a Time When" Interview Questions Like a Pro
Prepare a set of ~10 anecodotes from your previous experience and put them in 3 different buckets: Highlights, Working with others, and Tough times.
The Amazon Leadership Principles - A Complete Interview Guide
While this detailed post is about the Amazon's so-called Leadership Principles, the general approach can be used when interviewing for any company in talking about your experience.
| # This prints the current git branch when you submit an empty | |
| # line (i.e. press enter) in zsh | |
| # | |
| # Less distracting than adding it to your prompt, but still | |
| # very easy to run. | |
| git-status-on-enter () { | |
| if [ ${#${(z)BUFFER}} -eq 0 ]; then | |
| if git rev-parse --git-dir > /dev/null 2>&1 ; then | |
| echo |
This guide helps me set up my macOS laptop in a fairly simple manner. I'll need to go back to this guide roughly every 2–3 years. Maybe it'll help you, too!
Use Karabiner Elements
Map Caps Lock to Ctrl (when long-pressed) or Escape (when tapped). See this guide
Source: Eli Goldratt, Beyond the Goal