Why use triple-equal (===) in TypeScript? - Stack Overflow JavaScript as the target of compilation (TypeScript design goal 4) All TypeScript must be representable in JavaScript Further, it should be idiomatic JavaScript where possible Really though, the TypeScript compiler could use methods returning booleans for all comparisons, doing away with == and === entirely
When should I use ?? (nullish coalescing) vs || (logical OR)? 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) When the nullish coalescing operator ?? is supported, I typically use it instead of the OR operator || (unless there's a good reason not to)
Does Typescript support the ?. operator? (And, whats it called?) 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
In TypeScript, what is the ! (exclamation mark bang) operator when . . . 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
typescript - unknown vs. any - Stack Overflow TypeScript 3 0 introduces unknown type, according to their wiki: unknown is now a reserved type name, as it is now a built-in type Depending on your intended use of unknown, you may want to remove the declaration entirely (favoring the newly introduced unknown type), or rename it to something else
What is TypeScript and why should I use it instead of JavaScript . . . TypeScript is a superset of the JavaScript language that has a single open-source compiler and is developed mainly by a single vendor: Microsoft The goal of TypeScript is to help catch mistakes early through a type system and to make JavaScript development more efficient Essentially TypeScript achieves its goals in three ways:
Is key-value pair available in TypeScript? - Stack Overflow KeyValue interface exists in angular library that uses typescript So you have this generic interface to use if your project is angular Or you can use its declaration to get a nice generic KeyValue interface if you are not using TS in angular export declare interface KeyValue<K, V> { key: K; value: V; }
How do I dynamically assign properties to an object in TypeScript . . . TypeScript is used to catch (potential) errors at compile time If you cast to any to mute errors then you lose the power of typing and may as well go back to pure JS any should ideally only be used if you're importing code for which you cannot write TS definitions or whilst migrating your code from JS to TS