#!/usr/bin/env node "use strict"; var expect = function (val) { var object = { toBe: function (except) { if (except === val) { return true; } else { throw "Not Equal"; } }, notToBe: function (except) { if (except !== val) { return true; } else { throw "Equal"; } }, }; return object; }; console.log(expect(5).toBe(5)); // true console.log(expect(5).notToBe(5)); // throws "Equal"