What type is unknown

Create account Log in. Twitter Facebook Github Instagram Twitch. Let's understand with an example. Upload image. Submit Preview Dismiss. Sep 22, Dropdown menu Copy link Hide. Karishma Author Karishma Karishma. Jun 28, You need to perform type checking before using a variable of type unknown. In the example, you would simply need to check if callback is a function type:.

No type errors and no runtime errors! To be honest, I had difficulties understanding unknown when I had been learning it. How does it differ from any , since both types accept any value? The example above has demonstrated exactly the similarity and difference between unknown and any. The type of callback narrows to function type. Start discussion. A variable of type any can be assigned with anything: ts. Asked 3 years, 3 months ago. Active 3 days ago. Viewed k times.

TypeScript 3. Alexander Abakumov Jacoslaw Jacoslaw 4, 3 3 gold badges 12 12 silver badges 21 21 bronze badges. Add a comment. Active Oldest Votes. You can read more about unknown in the PR or the RC announcement , but the gist of it is: [.. Ilya 1 1 silver badge 12 12 bronze badges. Titian Cernicova-Dragomir Titian Cernicova-Dragomir k 17 17 gold badges silver badges bronze badges.

Anyone coming from C background, any is like dynamic and unknown is like object. I like unknown as it is just more type safe. Confusing names though. I don't know that this is a fair to compare unknown and object nawfal although I think I see what you're getting at in terms of the contravariance and covariance e. How I read it: unknown is I don't know ; any is I don't care — bozdoz. Awad Maharoof Awad Maharoof 2, 1 1 gold badge 26 26 silver badges 33 33 bronze badges. For example: let myVar: any; myVar[0]; myVar ; myVar.

Willem van der Veen Willem van der Veen 23k 14 14 gold badges silver badges bronze badges. The only answer to show use of as T , which will change the type from unknown to T. Very good. As I understand now even using them for some good time , any is basically using bare javascript. Zim Zim 1 1 silver badge 5 5 bronze badges.

Unknown If you write a function that only passes down an input to another function, use unknown. From this blog from ultimatecourses : Use the any type when there are no other options It's hard to find good examples for any.

Harsh Mangalam Harsh Mangalam 11 11 bronze badges. Sign up or log in Sign up using Google.