ip-num v1.3.2 has been released

ip-num is A TypeScript/JavaScript library for working with ASN, IPv4, and IPv6 numbers. It provides representations of these internet protocol numbers with the ability to perform various IP related operations like parsing, validating etc, on them.

A new version of ip-num, version 1.3.2 is now available.

This release contains one new feature and a bug fix.

Add method to split range into smaller ranges of certain size

In previous versions of ip-num, it was possible to take IP ranges with prefix less than /32 and split them into two. For example:

import {IPv4CidrRange} from "ip-num/IPRange";
import {IPv4Prefix} from "ip-num/Prefix";

let ipv4CidrRange = IPv4CidrRange.fromCidr("192.168.208.0/24");
let splitRanges: Array<IPv4CidrRange> = ipv4CidrRange.split();

// console logs:
// 192.168.208.0/25
// 192.168.208.128/25

splitRanges.forEach(range => console.log(range.toCidrString()))

But what if one needs to take an IP range and instead of just splitting into two, there is the requirement to split into a number of ranges with a specified prefix? Well, that is now possible with the addition of splitInto method:

import {IPv4CidrRange} from "ip-num/IPRange";
import {IPv4Prefix} from "ip-num/Prefix";

let ipv4CidrRange = IPv4CidrRange.fromCidr("192.168.208.0/24");
let splitRanges: Array<IPv4CidrRange> = 
ipv4CidrRange.splitInto(IPv4Prefix.fromNumber(26));

// console logs:
// 192.168.208.0/26
// 192.168.208.64/26
// 192.168.208.128/26
// 192.168.208.192/26

splitRanges.forEach(range => console.log(range.toCidrString()))

RangedSet.isCidrAble() incorrect results

Previous versions of ip-num failed to properly report that a string representing a single IP can be represented in the CIDR notation. This has now been fixed:

import {RangedSet} from "ip-num/IPRange";

let rangedSet= RangedSet.fromRangeString("1.2.3.4-1.2.3.4");

// now returns true
console.log(rangedSet.isCidrAble())

As always, ip-num is just an npm install or npm upgrade away.

Feel free to open an issue to discuss a feature or to report a bug.

Mapped Types in Typescript

This post will explore Mapped Types, another advanced feature of the Typescript type system. It is part of the Introduction to Advanced Types in TypeScript series.

A useful mental model to have when approaching some of the advanced type system features of Typescript is to view them as a mechanism for constructing other types from existing types. This view is spot on when it comes to mapped types as they are a mechanism that Typescript provides by constructing new types by mapping existing types into new ones.

This post would show how this looks like. It would be as beginner-friendly as possible, but having some knowledge of Generics, Union Types and Literal types in Typescript would be a plus.

To kickstart we take a quick again, at the keyof Operator, as it is essential to the workings of Mapped Types.

Conditional Types in Typescript

This post is about conditional types in typescript, which happens to be an interesting and powerful feature of the typescript's type system. It is part of the Introduction to Advance Types in TypeScript series.

Conditional types can be seen as a mechanism that allows us to perform ternary operations on types. 

Normally, ternary operations work with values, for example:

resulting value == true ? value A : value B
let value = 10
const isEven = value % 2 == 0 ? true : false

Conditional types gives us the ability to perform similar operation on types. Where we get a type out of two possibility, depending on the outcome of a check. 

any, unknown and never types in Typescript

This post will be a quick overview of three interesting types in Typescript: any, unknown, and never with the aim of quickly explaining what they are, and when to use them. It is part of the Introduction to Advance Types in TypeScript series.  

To start with, it is a good mental model to view Types from the perspective of set theory. This idea is fully explored in Union and Intersection Types in TypeScript, but for a quick summary, the idea is simple. When types are created, see it as similar to defining a Set. And what do sets contain? they contain objects. The next thing is to see values as objects that belongs to a set. A value defined to be part of a set, would not be allowed in a different set which it does not belong in or overlap with. 

Tuple Types in TypeScript

In this post, we would be looking at tuple types in TypeScript. It will also touch on generic rest parameters and variadic tuple types which are two of the advanced parts of tuple types. 

I'm on a roll! 😅

Just this Tuesday, 9th of March, at work, I was partly responsible for a partial downtime of a critical piece of the internet's infrastructure. 

This morning, I got two packages delivered to my place. One for myself, the other, to keep for my neighbor who wasn't at home. A combination of miscommunication with the delivery guy and excitement to unwrap my package, I ended up tearing up my neighbors package, mistaking it for mine! 😅. It was super awkward explaining my little mistake to her, when she came to pick her stuff up 😬. 

And fast forward to just a couple of hours ago, I mistakenly pushed a property file containing sensitive credentials to Github! Impact not super devastating but still, some damage control had to be done! 

It feels like I am on a roll here...what will I be tripping over next? What will the next gaffe be? Me dropping the database in production? 😅😬

Update: Two months after, no database was harmed :)

Spread and Rest in JavaScript

What does the rest parameter syntax look like? 

Simple, It looks like this: ...stuff

That’s cool. What about the spread syntax? What does that look like?

Well, it also looks like this: ...stuff

And this is why the spread and the rest parameter syntax could be confusing and easily misplaced for each other. They have precisely the same syntax! What then separates them? Answer is the context they are used.

This post will look into these JavaScript syntaxes with the aim of disambiguating them. The hope is that it helps in removing the confusion.