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 …

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 …

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

Feb 16, 2017 · It tells TypeScript to leave the expressions result as it is and pass it to JavaScript. It allows the use of JavaScript semantics in TypeScript, such as using loose equality (with the …

export function foo(arg: string): arg is MyType { return ... } I haven't been able to search for is in either the docs or google, it's a pretty common word and shows up on basically every page. …

Learn how to dynamically assign properties to an object in TypeScript with this helpful guide.

When creating or maintaining TypeScript definitions for pure JavaScript modules, interfaces should probably be used for everything that is a class in the original module; particularly …

Nov 5, 2015 · None of the other answers discuss how to run a TypeScript script that uses modules, and especially modern ES Modules. First off, ts-node doesn't work in that scenario, …

Mar 24, 2018 · TypeScript has three confusing types: {}, Object, and object. You can't assign undefined nor null to any of those types except if the strictNullChecks compiler option is disabled.

Aug 21, 2020 · TypeScript won't warn that lastName is never assigned and assumes its value is a string, when in fact it's not there and so reading its value will result in undefined.