NonFunctionPropertyNamesOf<T> Type

Extracts the names of all public properties of T that are not of type function. This includes properties defined using get syntax. Care should be used when using this type in conjunction with the object spread (...) operator, because the spread operator omits properties defined using get syntax and, therefore, so too does the type that TypeScript infers from that operator. get syntax. For example:

 class Thing {
    private _a = "a"; // a private variable
    public b = "b"; // a public variable
    public get c() { return "c"; } // a public property
    public d() { return "d"; } // a public method
    public e = () => "e"; // a public variable of type `function`
 }

 // The following can have the values "b" or "c" - those are the public, non-function properties of Thing.
 let nonFunctionProperty: NonFunctionPropertyNamesOf<Thing> = "c";

 // The following produces an error: "Property 'c' is missing in type '{ b: string; e: () => string; }' but required in type 'NonFunctionPropertiesOf<Thing>'"
 const thing1 = new Thing();
 const thing2: NonFunctionPropertiesOf<Thing> = { ...thing1 };

@see NonFunctionPropertiesOf to obtain a type that includes only these properties.

Defined in

Last Updated: 17 December, 2024