Promises and closures 😶🌫️
A simple Promise const getData = new Promise (( resolve , reject ) => { reject ( 'error' ); resolve ( 'data' ); }); getData . then (( res , err ) => console . log ( res )); getData . catch (( res , err ) => console . log ( res )); A promise can have resolve or reject Same way when you read the response, you can have resolve or reject. You can read them both or you can have a separate catch function. In the above example, we get "error" instead of "data" as it was rejected 1st const getData = new Promise (( resolve , reject ) => { resolve ( 'data' ); reject ( 'error' ); }); getData . then (( res , err ) => console . log ( res )); getData . catch (( res , err ) => console . log ( res )); This will give "data" and not "error" Static Functions of Promise ...