function myNew(fn, ...params) {
let obj = Object.create(fn.prototype);
const res = fn.apply(obj, params);
if (res && (typeof res === 'object' || typeof res === 'function')) {
return res;
}
return obj;
}
function App() {
this.a = 1;
}
const res = myNew(App);
console.log(res);