What is the TypeScript language? What can it do that JavaScript or available libraries cannot do, that would give me reason to consider it?

Jul 20, 2019 · In JavaScript, it's commonly seen as best practice to use === instead of ==, for obvious and well-known reasons. In TypeScript, which is one to be preferred? Is there even one which is …

Update March 2021: The newer TypeScript Handbook (also mentioned in nju-clc answer below) has a section Interfaces vs. Type Aliases which explains the differences. Original Answer (2016) As per the …

The ?? operator was added to TypeScript 3.7 back in November 2019. And more recently, the ?? operator was included in ES2020, which is supported by Node 14 (released in April 2020).

Jan 17, 2017 · Yes. As of TypeScript 3.7 (released on November 5, 2019), this feature is supported and is called Optional Chaining: At its core, optional chaining lets us write code where TypeScript can …

Jun 10, 2019 · I stumped on something in Typescript today. What does the three dots mean in this type? I can't find anything that explain this at all. I'm trying to do something like this let all: { readonly [key:

Apr 7, 2016 · Is key-value pair available in TypeScript? If so, how do I do that? Can anyone provide sample, example, or links?

Jun 22, 2018 · That is a "definite assignment assertion": varname !: sometype informs typescript not to worry about checking if varname might be unassigned (it tells typescript that varname will definitely …

What does the ampersand (&) mean in a TypeScript type definition? Asked 9 years, 6 months ago Modified 1 year, 1 month ago Viewed 97k times

Jan 26, 2017 · I found the following in a TypeScript declaration file for Angular: interface IDirective{ compile?: (templateElement: IAugmentedJQuery, What does the ?: after compile do?