Why use unknown when we have any in Typescript? Type inferences are powerful and allows us to do magic when we don’t know types. 1 2 3 const i: any = 1; console.log(i); // 1 unknown seems to do the same thing. 1 2 let x: unknown = 1; console.

Let’s get to know interfaces for functions - yes, that’s a thing. We have seen interfaces used as types and interfaces as array types. Since function is an object and interfaces are supported on other objects, they should be supported on functions also. Right? You betcha. What is this blog if we can’t write about all the stuff that no one care’s about?

It’s not the why, but more on what of ‘modules’. No Javascript is an island. It was an island about two decades back but Javascript has done some pretty good land reclaimation to form large continents now. So it goes without saying that these are not the days of writing Javascript or Typescript in <script> tag in a single HTML.

Interface an interface. If that doesn’t excite you, I don’t know what will. We have seen interfaces used as types before. But as our God Goop says - “abstract; (while && when) you can;”. So, we are here to know about interfaces for interfaces. Consider this simple example - 1 2 3 interface Borg { name: string; } Now, any class implementing the interface Borg will have a name attribute.

What exactly are interfaces for arrays? Previously we have seen interfaces as types. Interfaces provide useful abstraction on class and can be useful in tricky situations with complex types. But, what about interfaces for array? It turns out interfaces can be as easily applied for array types as well. They are just super useful as interfaces that define complex types and make arrays type-safe - nothing more, nothing less.

Let’s talk anonymous functions and make them, well, “not anonymous”. Anonymous functions are just functions without names. If you have been following this blog, or have written some Javascript - you surely would have come across them. Anonymous functions are just function expressions. Let’s see a quick example. The following code block has a ‘named’ function.

Why and how of using abstract classes in Typescript. We have seen a bit of classes and objects in Typescript previously. There was however a key aspect of object oriented programming missing there. Although we discussed inheriting classes, we never mentioned abstract classes. Sacrilege, that. On the other hand, anything goes for the daily blogging gobble-gobble.

Use non-numbers in Typescript enums. enums have the following typical definition and usage - 1 2 3 4 5 6 7 8 9 enum Colors { red, blue, green } console.log(Colors[1]); // blue Or, the numbers can be explicitly specified.. 1 2 3 4 5 6 7 8 9 10 11 12 enum Colors { red = 1, blue = 2, green = 3 } console.

Decorate a class, member or property to signify its specialty. Decorators are not available in Javascript but enable us to enhance our Typescript libraries and code. Decorators are experimental features in Typescript at this time. A decorator is a way to annotate or modify a class, properties, functions or parameters. Decorator is specified against a target class, and has a body that indicates the decorator’s function.

“Typecast types in Typescript” : that’s three “types” in a sentence with three significant words, and for that, I should tap out (but I don’t). We see a lot about “type assertions” in to type conversations (or conversions!) in Typescript. Type assertions enable you to override default type inference for neutral types.

How are collections typed in Typescript? Primitives are fairly easy to type - we have seen this while discussing Typescript and its types. 1 2 const num: number = 0; const msg: string = "hello"; We have seen examples of typed arrays in the same post, but how about all the other collections?

Typescript supports public, private and protected modifiers that affect the accessibility of class in different ways. Access modifiers further a core concept of object oriented programming - ‘encapsulation’. The accessibility of variables and members of a class are driven by modifiers and therefore controlled in the programming flow. Let’s start with a simple class example.

Typescript allows use of static variables and methods just like modern Javascript. Static variables and methods are declared with a keyword static. Static variables Static variables exist within the class context, and are not carried forward to the object of the class. Define a static variable like so - 1 2 3 class Human { static chaos: boolean = true; } The variable value is accessible using the class.