fetch from backend

fetch(`http://10.58.0.37:8000/music/add/${props.id}`, {
        method: "POST" ,  
        headers: {  
            Authorization: "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6Indsc3hvMjExMkBuYXZlci5jb20ifQ.i9ZWIGY6MUxYXcL344nsrwBiXD4hpvEavLGdYfaBSOs",
        },
        body: JSON.stringify({
            music_id: props.mkList,
        }),
        })
        .then(response => response.json())
        .then(response => 
            {
              if(response.count === 0){
               alert("이미 담은 곡입니다.");
              }else if(response.count>=1){
                  alert(response.count+"곡이 담겼습니다.");
              }
            }
         );

The example above is a full example on the use of the Fetch API;

Every fetch requires an API Address. The address above is in the shape of

`http://10.58.0.37:8000/music/add/${props.id}`

The http://10.58.0.37 section is the IP address of the API
:8000 is the port number
/music/add is the end point
/${props.id} refers to the url parameter. By adding a value at the end of the API address you can send additional info with the request.
/${props.id} query strings can also be added to the end.More info on another blog

The API address tells the fetch method, which backend API to send the request to.