catch fetch ERR_CONNECTION_REFUSED

Question

I must be getting old google searches because I can't find any threads on how to do this if you are using javascript's fetch not the old XMLHttpRequest

I am trying to test whether or not my VM is online. The rest of the VM is locked down but I left an open endpoint for testing.

I tried using the status to check if the server is up but gave me a different error than a response error:

fetch("https://rockosmodernserver.westus2.cloudapp.azure.com/ ", {
            method: "GET",
            }).then(response => response)
            .then(data => {
                if (data.status == 200){
                    console.log("server is up")
                }
                else{
                 console.log("server is down!!")   
                }
            })

It works if the server is up but if the server is down I get:

VM739:1 GET https://rockosmodernserver.westus2.cloudapp.azure.com/ net::ERR_CONNECTION_REFUSED

when I tried googling this I got solutions for XMLHttpRequest but not for the fetch module.

Answer 1

You looking for catch block. In the catch block you can fetch the errors. Imn the example below you have access to the error object.

fetch("https://rockosmodernserver.westus2.cloudapp.azure.com/ ", {
    method: "GET",
    }).then(response => response)
    .then(data => {
        console.log("server is up")
    })
    .catch((error) => {
      console.error('Error:', error);
      console.log("server is down!!")   
    });