encode/decode base64 with JS

Encoding to base64 is done with the btoa command

btoa("This is a test.")
> "VGhpcyBpcyBhIHRlc3Qu"

To decode a base64 encoded string, use the atob command

atob("VGhpcyBpcyBhIHRlc3Qu")
> "This is a test."

Có thể bạn đã miss một số snippets code

flatMap()

Use flatMap() creates a new array with sub-array elements flattened by specified depth.

promise + gì

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