Questions from the chat (truncated to include questions and comments to the questions) Most were answered during the call.

14:01:51 EAT From Mark Ng'ang'a : We’re live.

From Ho Slack : Please walk through the JS file for a second.

From Stanley Ndagi : Ho Slack, please remember to ask Muchai to do that after she's concluded

From Ryan Marvin : Please feel free to post any questions that come to mind here and Muchai will answer them at the Q&A at the end

From Moffat : Question: I noticed in some places, the boolean operator “OR” is used as “ | “ and in other places “ || “. Do they have any difference?

From joy warugu : what's the difference between types and interfaces and when do you choose one over the other

From creez : +100 @ joy

From Bonny Mwenda : How do you go about introducing typescript to an old code base? Eg, what are the best practices

From Stanley Ndagi : Do you setup files and include @ the same time in the .tsconfig? Or does include disregard the files?

From creez : I normally see people using custom types and others using interfaces…What is the difference and when should I use types over interfaces and vice verser.

From Paul Kiplimo Morogo : is there a standard naming pattern for interfaces? I see a lot of them defined with prefix ‘I’ ie IUser, IResponse etc

From Ho Slack : Yeah @ Bonny’s Question. Can I introduce Typescript in my react JS codebase without breaking other things?

From Stanley Ndagi : Difference between .tsx and .ts file extensions?

From Moffat : Does the compilation step affect the performance of TS compared to JS?

From creez : Tax is when you have tsx in your code base ts is when you aint using jsx

From Kelvin Chirchir : How do you handle a function that returns a Promise

From Mo : Why not put the JS files in the same folders as the TS files?

From Brian Odhiambo : @ stanley .tsx is syntax sugar. Typescript XML - Mostly for React not sure about Vue. …. .ts a typescript file

From Lemayian : I understand that I can use ts-node to run typescript code directly, but I have not seen this being used in production. Does this mean that typescript is less performant than JS? Basically, why can’t I just run TypeScript straight on my web server without transpiling to JS?

From joy warugu : the qn about type set user | null and ?... they aren't the same .. opro

From Gilbert N : At what instance do we declare our own types using declare keyword.

From joy warugu : optional ? means you whatever can be undefined..not null

From joy warugu : so it would be the same as user | undefined

From Lemayian : Interface vs Types: ducba.com/typescript-type-vs-interface/

From creez : Yeah Thanks @ josee

From Paul Kiplimo Morogo : @ Lemayian TypeScript is simply a superset of JavaScript which allows us the advantages of a statically typed language during development but it still has to be transpiled to normal JS

From zacharianjoroge : Can we say that interfaces allow polymorphism like in Java

From david ngugi : Interfaces simply just describe the structure of say a class…it’s properties and methods

From Austin Roy : There’s also a great cheat sheet for TS with React

From Paul Kiplimo Morogo : Typescript is like a stubborn and hard-headed spouse but with minimal maintenance, JavaScript is the easygoing and fun partner who can drag your marriage through hell in the long run