ofClass

arrayOf :: String → a → Boolean

Takes the name of a valid javascript class in form of string (for example: 'String', 'Date', 'BigInt', etc) then returns a new function reporting whether the received value is an instance of that class.

ofClass is the backbone of all the type validators:

isString.js

import ofClass from './ofClass';

/**
 * Evaluates whether the given value is of type string
 * @param value
 * @returns {boolean}
 */
const isString = ofClass('String');

export default isString;

ofClass rely on Object.prototype.toString to check on the received value type in order to avoid typeof weird behaviours and encouraging a runtime strict type validation.