I'm not 100% sure what you're asking for here, but here is my method based on my own interpretation of your question using a call from GitHub's API. We are using fetch to pull the data. Our .then is our resolve, and our .catch is our reject.

const url = 'https://api.github.com/users'

const callApi = function(fetchUrl){
    fetchUrl = url
    fetch(fetchUrl)
        .then(response=>{
            return response.json(); // Turn data to JSON
        })
        .then(data=>{ // If it was successful, this below will run
            console.log(data) // Do whatever you want with the data from the API here
        })
        .catch(err=>{ // If it was unsuccessful, this below will run
            console.log(err); // Console log the error
            setTimeout(callApi(url), 200); //If it failed, try again in 200ms
        })
}

callApi(url) // Initial function call

Some things to note: If you're using an API that limits the number of calls you can make in a day/month, this will eat up through those allotted requests really quickly.