JS workshop

The JS workshop holds the JavaScript the course assumes, in ten units. Every unit explains a topic briefly, shows it with examples from Lorraine Commons and ends with exercises at three levels with solutions.

You can work through the units in order or only through the ones the entry test recommends. When a chapter assumes a topic, it points you to the matching unit.

Running the examples

Below every example there is a "Run" button. The program then runs right in the browser, and its output appears below the code. "Edit" lets you change the code and run it again, and "Reset" restores the original. Predict what a program prints first, and only then check.

The examples of the unit "The DOM and events" are small HTML pages. They appear in a frame below the code, with the console output underneath.

All examples are also in the course repo under examples/js, one folder per unit. There you run them with Node.js.

cd examples/js/variables/en
node types.mjs

The units

Unit	Contents	Needed in the course
Variables, types and operators	let and const, primitive types, comparisons, what counts as true and false, ??	everywhere
Control flow	if and else, the conditional operator, switch, loops with for...of and while, break and continue	everywhere
Functions and scope	functions and arrow functions, default values, scope, closures	from part 1, composables in part 5
Objects and arrays	objects, arrays, references, spread, destructuring, optional chaining	from part 1
Strings and template literals	template literals, string methods, search that ignores case, sorting	search and filter from part 3
Classes and this	classes, private fields, getters, static methods, this and bind	error classes of your own, reading code with this
Handling errors	throw, try, catch and finally, error types, error classes of your own	data from the server in part 1 and part 7
The DOM and events	finding and creating elements, events, event delegation, forms	the SPA built by hand in part 2
JSON and data formats	JSON.stringify and JSON.parse, dates, copies with structuredClone	data from the server, saving in the browser
Formatting numbers and dates	amounts in francs, date and time, time zones with Intl	wherever the app shows amounts and dates

Anything beyond these basics is in part 1, such as modules, values and references in detail, map, filter and reduce, and asynchronous JavaScript with fetch.