Tránh viết biến có phạm vi global

Không nên

    var map = document.querySelector("#my-map");
    map.style.height = "600px";
Nên
!function(){
    var map = document.querySelector("#my-map");
    map.style.height = "600px";
}()

Có thể bạn đã miss một số snippets code

Getting the last element of a split string array

Promise + gì

promise + gì

Copy a string to the clipboard

Copy a string to the clipboard. Only works as a result of user action (i.e. inside a click event listener).

Extend Object javascript

Spread Operator for Objects

Using the spread operator during an Object declaration will assign the properties of the referenced Object to the new Object.