Detect when your site is visible to users

tipjs,web_developer

document.onvisibilitychange = function () {
          document.visibilityState === "visible"
             ? (document.title = "👋 Hello")
             : (document.title = "😟 Bye!");
       };

using javascript callback style error handling

Làm phẳng mảng dùng phương pháp đệ quy

Promise + gì

Converting Object to an Array

group by property javascript use reduce