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 preferable ...
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 immediately stop running some expressions if we run into a null or undefined. The star of the show in optional chaining is the new ?. operator for optional property accesses. Refer to the TypeScript 3.7 ...
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).
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 convenience of omitting all the checks) or using the (loose) inequality comparisons.
The key aspect to interfaces in typescript that distinguish them from types is that they can be extended with new functionality after they've already been declared.
I found the following in a TypeScript declaration file for Angular: interface IDirective{ compile?: (templateElement: IAugmentedJQuery, What does the ?: after compile do?
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 be assigned, even if typescript cannot infer where it is assigned). Normally typescript will check if the variable may be unassigned, and gives errors. For more information, see: https://www.typescriptlang ...
