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 …

Feb 16, 2017 · In TypeScript, what is the ! (exclamation mark / bang) operator when dereferencing a member? Asked 8 years, 9 months ago Modified 6 months ago Viewed 653k …

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

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. …

Feb 22, 2016 · 10 Type guards in typescript To determine the type of a variable after a conditional statement you can use type guards. A type guard in typescript is the following: An expression …

Yes, your example of defining an interface only for the particular items would be a more useful way to do it. It would be quite rare to have an array of items, but not want to conveniently …

Jul 26, 2018 · You can't get the results of the TypeScript type query operator at runtime, because the type system is erased at runtime. You need to give up on the typeof operator. What you …

Jun 17, 2020 · Double double questionmarks in TypeScript Asked 5 years, 4 months ago Modified 2 months ago Viewed 87k times

Jun 22, 2018 · 84 That is a "definite assignment assertion": varname !: sometype informs typescript not to worry about checking if varname might be unassigned (it tells typescript that …