We’ve already talked about interfaces in TypeScript, some with our discussion on Custom Data Types. However, we can go further with what they can do. So we previously had an interface that looked something like: However, we might not want, or even need, all of those properties. Therefore, we can make some of them optional,…
It is common to write a function where the return data type is related to the data type(s) of the parameters passed to the functions. Let’s look at an example of this: This function will return the first element of an array. However, it uses the any data type to allow for any type of…
The tsconfig.json file specifies the root files and the compiler options required to compile a TypeScript project. So presence of a tsconfig.json file in a directory indicates that the directory is the root of a TypeScript project. Without that file, the compiler will continue to move up the directory hierarchy to fine the config file. There is also a…
People, when they come to TypeScript, might have different ideas in mind with how strict they want types checked. Some people don’t want types at all, like JavaScript currently is, and want to use other aspects of TypeScript, while others might want to be very strict. The default experience with TypeScript, where types are optional,…
Once we’ve created our first TypeScript file, we need to convert it to JavaScript if we want our browsers (or Node.JS) to run it. There are several online sandbox tools to let you write code, but they won’t convert it to JavaScript, at least none that I’ve found yet. To set it up, you will…
We’ve already seen the standard data types in JavaScript and TypeScript. However, JavaScript allows for class, and we want to therefore be able to define a custom data type within TypeScript. Since JavaScript supports classes and object-oriented programming, so does TypeScript. You can explicitly describe this object’s shape using an interface declaration. Then, to define an object…
We already looked at the very first script in TypeScript, but it buys us nothing new. So let’s look at how we can use typed variables, and how it will stop errors, on a simple scale. So if we want to expand on our first example, we might want to use a variable. Now TypeScript…
You will need to install the TypeScript engine for you to use TypeScript. This is because your TypeScript code must be converted into JavaScript, so it needs a program called a transpiler to do the conversion to JavaScript so that a browser can run it. What does a Transpiler Actually Do? A transpiler is not…
