web-work.js

self.addEventListener('message', (ev)=>{
    //console.log('Web worker started with data: ', ev.data);
    
    let data = ev.data.do;
    switch(data){
//        case 'Get Started':
//            self.postMessage('Web Worker Started');
//            break;
//        case 'Other':
//            self.postMessage('Other task...');
//            break;
        case 'fetch':
            let url = 'http://jsonplaceholder.typicode.com/posts';
            console.log('about to do the fetch for the data');
            
            fetch(url)
            .then(response=>response.json() )
            .then( data =>{
                self.postMessage( JSON.stringify(data) );
            })
            .catch(err=>console.log(err));
            
            break;
        default:
            console.log('Invalid access');
            self.postMessage('Closing web worker');
            self.close();
    }
    
})