When TypeScript first landed in public view in October 2012, the type annotations looked a bit funky. If you were a student of type theory, they would have been familiar; but most programmers wouldn’t have seen a type annotation like this before: var name: string; Given the popularity of putting type names before variable names, […]
IntelliCode brings AI-assisted power-ups to your auto-completion. It has been in preview within Visual Studio for some time (you can read about Visual Studio IntelliCode here) – but it has now landed in Visual Studio Code, which is exceptionally handy if you’re a TypeScript programmer like me. So what is IntelliCode? It’s a simple VSCode […]
It is pretty common to want to hydrate a class from a JSON value obtained in a service. If you just parse the JSON you get the properties, but not the behaviours that you expect. As this is a reasonably common problem to solve, it is worthing doing it just once. The following function will […]
I have been working out how to create a TypeScript NotFunction type for a while, in response to a Stack Overflow question. With the arrival of conditional types, I think there may be a way. It’s not perfect – but it does work. The type works by taking all possible types and converting the type […]
The C# 8.0 announcement included a note on default implementations of interface members. If you’ve been programming for long enough, this might make you a little nervous at first thanks to the hangovers of multiple inheritance. Before you chuck out this idea, though, let’s look at it from a different perspective. I’m going to talk […]
This is one of those cases where a question keeps cropping up, so lots of people are trying to do something that the TypeScript Compiler doesn’t like very much. Yes, it’s time to talk about the TypeScript Dictarray! What’s a Dictarrary? It’s a dictionary that’s also an array. You know… one of these: const dictarray […]
Don’t worry, the mechanism for creating TypeScript mixins hasn’t changed, but I just wanted to demonstrate that the technique described in TypeScript Mixins Part Two is valid for use with static properties. Reusing the original example, let’s see what happens if we add static properties to our Flies and Climbs mixins. Not only does this […]
I had a question from Bruce about ECMAScript modules following on from my post on not mixing namespaces and modules in TypeScript. The question was: How can a module create something that can be used in browser without creating a variable on the global scope? This is a great question, so here is a quick […]
Cypress is a front-end testing utility that allows you to write UI tests using Mocha and Chai. It has auto-waits, time-travel (look back at snapshots from within test runs), and automatic discovery of tests. This blog provides a quick start for getting started with Cypress and TypeScript. Cypress NPM Packages Your package.json file will need […]
This is just a short note on how to use an ECMAScript Proxy to intercept methods. There are plenty of examples that intercept properties, but examples with methods seem absent currently. For demonstration purposes, we’re going to intercept a very famous method. The console log method takes any number of arguments of any type. This […]