Barcode Writer in Pure JavaScript

The Console now supports redeclaration of const variables across separate REPL scripts (such as when you run a statement in the Console), in addition to the existing let and class redeclarations. This support allows you to experiment with different declarations for const variables without refreshing the page. Previously, DevTools threw a syntax error if you redeclared a const binding.

In practice, we usually also need another tool to provide an API to control the browser (e.g., ChromeDriver).

“System tests” is a common naming for automated end-to-end tests in the Rails world. Before Rails adopted this name, we used such variations as feature tests, browser tests

This poses a few problems for automation. In some environments, there may be no graphical display available, or it may be desirable to not have the browser appear at all when being controlled.