Set a Typescript array as undefined

Question

I'm developing an Angular 2 application. This the first time I do something with Angular or Typescript.

I have this variable inside of a class:

public products: IProduct[];

IProduct is:

interface IProduct {
    productCode: string;
    description: string;
    lawId: number;
    name: string;
    comment: string;
    emvoProduct?: IEmvoProduct; // ?: Optional.
}

Is there any way to set it to undefined?

When I do this:

this.products = undefined;

I get an error saying:

(TS) Type 'undefined' cannot be converted to type 'IProduct[]'.

Answer 1

Its because of strictNullChecks compile option in your tsconfig.json; you can simply remove or set to false.

Alternatively, you have to specify that the field can be undefined:

products: IProduct[] | undefined

Another alternative is to delete

delete this.products

this will truly make the field undefined when you check for it because its simply not there. typescript will be happy with it -- even with strictNullCheck: true