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
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
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:
What does the ampersand ( ) mean in a TypeScript type definition? "Intersection" refers to the resulting type, not the operation performed on the properties An object belonging to both Type A and Type B must have all properties in A (so that it is an instance of A) while also having all the properties of B (so that it is also an instance of B)
typescript - What does the as keyword do? - Stack Overflow That is not vanilla JavaScript, it is TypeScript as any tells the compiler to consider the typed object as a plain untyped JavaScript object The as keyword is a Type Assertion in TypeScript which tells the compiler to consider the object as another type than the type the compiler infers the object to be
TypeScript, Looping through a dictionary - Stack Overflow @Ian The problem is that there are too many libraries which do modify object prototypes It seems a bad idea to advocate this type of pattern when much better simple alternatives exist, such as Object keys(target) forEach(key => { let value = target(key); * Use key, value here * });
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