Category: Programming

Javascript exception tracebacks

Working with browser Javascript on mobile devices, I found myself needing to report exceptions back to a server. (It’s hard to see the browser console log on a mobile device without connecting it to a desktop machine). Here’s what I did to make a suitable object that can be serialized. To use this you’ll need stacktrace.js loaded in your web… Read more →

Find peak cases

This entry is part 4 of 4 in the series Exploring data with SQL

Back in the Database Programming section of this series, we created the view named us_counties_new, showing the daily new case load. Recall that we first computed the seven-day running average of the total case loads in the us_counties_avg7 view, then used those numbers for the daily case loads. Having the daily case loads available lets us do some interesting analysis.… Read more →

Getting started with the data

This entry is part 2 of 4 in the series Exploring data with SQL

The Times’s data is here. If you’re using a browser, open the context menu (right-click) on that link and use the Save Link As … operation to put it into a file on your system. We’ll use it later to load the database. Use your database interface program to log in to your database server, and figure out which… Read more →

Explore pandemic data with SQL

This entry is part 1 of 4 in the series Exploring data with SQL

The New York Times newspaper publishes, every day, a file showing COVID-19 cases and fatalities for each county in the USA. They put their file on github here for anyone to use. So, let’s use it. Let’s download it and learn a few things about using SQL to explore data as we dig into it. Their file is called us-counties.csv.… Read more →

Choropleths: color-coded maps showing data by state or other geography

A Choropleth is a colored map, typically showing information gathered by some kind of census. A well-known example is the New York Times’s COVID-19 map. Let’s say you have some data that’s coded by geographic area. For example, you might have a table showing the number of COVID cases per 100,000 people county by county in Massachusetts. It might look like… Read more →

Safari web extensions compatible with the rest of the world

About time! Apple announced in Safari 14, Web Extensions will be compatible with those used by Chromium and Firefox. They’ve bravely added a tool to XCode to help people convert their old Safari extensions to the what they call the new format. Most people probably won’t find that useful, having converted their Chromium extensions to work on Safari in the… Read more →

getDisplayMedia vs. getUserMedia

I’ve been messing around with the browser API navigator.mediaDevices.getDisplayMedia(). The question I hoped to answer: can I capture the content in some computer display surface and push it through the same sorts of process that I use with .getUserMedia()? I tested on Google Chrome 84. Answer: yes. It has some quirks. It doesn’t need, and indeed rejects, elaborate constraints.  {… Read more →

New Microsoft Edge rolls out to everybody this month

About time! the new Chromium-based Edge browser will show up on Windows 10 machines in this month’s update. For the cancelled Internet Explorer and Legacy Edge project people, I would have more sympathy if their work products hadn’t baffled software developers for a quarter-century. IE and old Edge were in the uncanny valley of compatibility. They worked well enough that… Read more →