Angular UI Development with PrimeNG

Type inference

Type inference is used when the type is not provided explicitly. For instance in the following statements:

var x = "hello";var y = 99;

These don't have explicit type annotations. TypeScript can infer that x is a string and y is a number. As you see, the type can be omitted if the compiler is able to infer it. TypeScript improves the type inference continuously. It tries to guess a best common type when elements of several types are present in an array. The type of the following variable animal, where Sheepdog extends Dog, is Dog[]:

let animal = [new Dog(), new Sheepdog()];

The best common type of the next array is (Dog | Fish)[] because the class Fish doesn't extend to any other class:

class Fish {  kind: string;}let animal ...