类型参数类的Typescript泛型约束

Question

How can you put a constraint on a TypeScript type parameter. In c# you can use the construct { where T:class} ?

Answer 1

Does Typescript support constraints on type parameters like c# { where T:class}.

Yes. Syntax is of the form <T extends SomeClass> instead of <T>

Example

interface Foo{
    foo: number;
}

function foo<T extends Foo>(foo:T){
    console.log(foo.foo);
}

foo({foo:123}); // okay
foo({foo:'123'}); // Error

Note that types in typescript are structural ( why ) which means that classes and interfaces are handled the same way as far as the generic constraint is concerned.