# Constructor A _Function_ instance that's a _constructor_ (either regular function or _class_) ## `constructor/is` Confirms if given object is a constructor function\_ ```javascript const isConstructor = require("type/constructor/is"); isConstructor(function () {}); // true isConstructor(() => {}); // false isConstructor(class {}); // true isConstructor("foo"); // false ``` ## `constructor/ensure` If given argument is a _constructor function_, it is returned back. Otherwise `TypeError` is thrown. ```javascript const ensureConstructor = require("type/constructor/ensure"); const fn = function () {}; ensureConstructor(fn); // fn ensureConstructor(() => {}); // Thrown TypeError: () => {} is not a constructor function ```