call-generator.js

function checkLogs(opts) {                                                                                                                                     
    // Initialize the array where we store our messages (only called the first time)                                                                           
    if (!opts.hasOwnProperty('messages')) {                                                                                                                    
        opts.messages = [];                                                                                                                                    
    }                                                                                                                                                          
                                                                                                                                                               
    // Make the initial call to get the generator, specifying the url to get the first page of data                                                            
    if (!opts.hasOwnProperty('logs')) {                                                                                                                        
        opts.logs = getLogs(initialUrl);                                                                                                                       
    }                                                                                                                                                          
                                                                                                                                                               
    let { logs, messages, onComplete } = opts;                                                                                                                 
                                                                                                                                                               
    let next = logs.next();                                                                                                                                    
                                                                                                                                                               
    // Get the result of the most recent ajax call from the generator function                                                                                 
    next.value.then(data => {                                                                                                                                  
        if (data) {                                                                                                                                            
            const {items, paging} = data;                                                                                                                      
                                                                                                                                                               
            // If we still have data, append it to our list of messages                                                                                        
            messages = messages.concat(items);                                                                                                                 
                                                                                                                                                               
            // Then call ourselves again to get the results of the next ajax call                                                                              
            checkLogs({logs, messages, onComplete});                                                                                                           
        } else {                                                                                                                                               
            // If we don't have any more data, call our callback with the complete list of messages                                                            
            onComplete(messages);                                                                                                                              
        }                                                                                                                                                      
    });                                                                                                                                                        
}