★ isNumber()


Checks if any value is a number type, or the type obtained from its object class equal to 'number' or an object type and an instance of Number. The value is also checked by the Number.isFinite() method to determine whether it's finite and is validated by the Number.isNaN() method.

const isNumber = <
  Type extends AnyNumber = number,
  Payload extends object = object
  value: any,
  callback: ResultCallback<any, Payload> = resultCallback,
  payload?: Payload
): value is Type =>
    (typeof value === 'number' ||
      ((typeOf(value) === 'number' || typeof value === 'object') &&
        value instanceof Number)) &&
      !Number.isNaN(value.valueOf()) &&

Generic type variables


A generic type variable Type constrained by AnyNumber indicates the number type of the given value via the return type, by default number.


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


value: any

The value of any type to check.

callback: ResultCallback<any, 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 Type

The return type is a boolean as the result of its statement indicating the value is a generic type variable Type constrained by AnyNumber by default of number type.


The return value is a boolean indicating whether the provided value is a number type or an instance of Number.

Example usage

// Example usage.
import { isNumber } from '@angular-package/type';

isNumber(10304050); // true, value is number
isNumber(Number(10304050)); // true, value is number
isNumber(new Number(10304050)); // true, value is number
isNumber<Number>(new Number(10304050)); // true, value is Number

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