javascript - Typescript function taking one or array of objects

Question

We are using simple function declaration quite a lot where function takes either single object or array of objects of some type.

Simple declaration is:

interface ISomeInterface {
    name: string;
}

class SomeClass {
    public names: ISomeInterface[] = [];

    public addNames(names: ISomeInterface | ISomeInterface[]): void {
        names = (!Array.isArray(names)) ? [names] : names;
        this.names = this.names.concat(names);
    }    
}

But TypeScript throws "type is not assignable" error.

Is there better way of doing this? Obviously we could have two separate functions, but I think handling single vs multiple this way is quite fine.

Answer 1

You can make it easier

 addNames(names: ISomeInterface | ISomeInterface[]): void {
        this.names = this.names.concat(names);
 } 

From MDN

The concat() method returns a new array comprised of the array on which it is called joined with the array(s) and/or value(s) provided as arguments.