isInstance()

isInstance()

Checks if any value is an instance of a given constructor.

const isInstance = <Obj, Payload extends object>(
  value: any,
  constructor: Constructor<Obj>,
  callback: ResultCallback<
    any,
    { ctor: typeof constructor } & Payload
  > = resultCallback,
  payload?: Payload
): value is Obj =>
  callback(
    isObject(value) &&
      typeof constructor === 'function' &&
      constructor instanceof Function
      ? value instanceof constructor
      : false,
    value,
    { ...payload, ctor: constructor } as any
  );

Generic type variables

Obj

A generic type variable Obj, by default captured from the provided constructor, indicates the type of generic type Constructor, and the type of value parameter via the return type value is Obj.

Payloadextendsobject

The Payload generic type variable constrained by object indicates the type of optional parameter payload of the supplied callback function and payload optional parameter of the isInstance() function from which it captures its value.

Parameters

value: any

The value of any type to be an instance of a given constructor.

constructor: Constructor<Obj>

A class or function that specifies the type of Constructor.

callback: ResultCallback<any, { ctor: typeof constructor } & Payload>

A callback function of ResultCallback type with parameters, the value that has been checked, the result of this check, and payload of generic type variable Payload with optional properties from the provided payload, to handle them before the result return. By default, it uses resultCallback() function.

payload?: Payload

An optional object of the generic type variable Payload is assigned to the payload of the given callback function.

Return type

value is Obj

The return type is a boolean as the result of its statement, indicating the value is a generic type variable Obj by default of type captured from the supplied constructor.

Returns

The return value is a boolean indicating whether the provided value is an instance of a given constructor.

Example usage

Basic usage

Parameters callback and payload

Function constructor