jExcel – the JavaScript spreadsheet

Tables on the web are always challenging. Whether you do them by hand, or with the help of a framework or library, they often carry a lot of complexity, performance costs, and compatibility issues.

Recently I came across jExcel, which seems to be quite powerful, with lots of advanced features, and, at the same time, rather simple to use. The recent release of version 3, brings even more features and improves on the existing ones:

  • Drag and drop columns
  • Resizable rows
  • Merge columns
  • Search
  • Pagination
  • Lazy loading
  • Full screen flag
  • Image upload
  • Native color picker
  • Better mobile compatibility
  • Better nested headers compatibily
  • Amazing keyboard navegation support
  • Better hidden column management
  • Great data picker: dropdown, autocomplete, multiple, group options and icons
  • Importing from XSLX (experimental)

Have a look at some of the usage examples too.

termtosvg – record terminal sessions as SVG animations

termtosvg (GitHub repo) is a handy little tool that makes recording animated sessions in the terminal as simple as humanly possible. Instead of generating heavy graphics or video animations, this tool creates SVG files, which are a lot smaller and easier. There is also a selection of themes to choose from.

Th resulting SVG files can be used as quick demos and guides in READMEs on GitHub, or as tutorials for your application’s website.

How HTTPS Works in 10 Minutes

How HTTPS Works in 10 Minutes” is a simple, high-level overview of how HTTPS works. It doesn’t dive into too much detail or heavy math. But it does cover the main stages of how the connection is established, verified, and encrypted. These are the stages that are covered:

  1. You go to an HTTPS website via your browser
  2. The Client says “Hello”
  3. The Server says “Hello”
  4. The Client makes sure the SSL certificate is legitimate
  5. The Client gets the public key from the SSL certificate
  6. The Client uses the public key to make more random bytes
  7. The Client and Server make session keys
  8. The Client and Server compare session keys
  9. If the session keys match, game on

Calculating distance using MySQL

Calculating distance using MySQL” is a very useful blog post for everyone who works with geographical location data and MySQL. It shows a simple example of how to calculate the distance between two coordinates on a sphere (Earth in particular) within the MySQL itself.

SELECT ST_Distance_Sphere(
    point(-87.6770458, 41.9631174),
    point(-73.9898293, 40.7628267)
);

The above will return 1148978.6738241839, which is the distance between the two points in meters.

This functionality is available since MySQL 5.7. Have a look at the documentation of the spacial convenience functions.

MariaDB has similar functionality, but with a slightly different function names. Use ST_DISTANCE() instead of ST_Distance_Sphere(). Have a look at this blog post for more details.