Async/Await try-catch handling

by Uday Hiwarale

HTML

<script src="https://rawgit.com/eu81273/jsfiddle-console/master/console.js"></script>

JavaScript

const a = () => new Promise( resolve => {
    setTimeout( () => resolve( 'result of a()' ), 1000 ); // 1s delay
} );

const b = () => new Promise( ( resolve, reject ) => {
    setTimeout( () => resolve( 'result of b()' ), 500 ); // 0.5s delay
} );

const c = () => new Promise( resolve => {
    setTimeout( () => resolve( 'result of c()' ), 1100 ); // 1.1s delay
} );


const doJobs = async () => {
	try {
        var resultA = await a();
        var resultB = await b();
        var resultC = await c();
    
        return new Promise( ( resolve ) => {
            setTimeout( () => {
                resolve( {
                    values: [ resultA, resultB, resultC ]
                } );
            }, 3000 );
        } );
    } catch( error ) {
        return [ null, null, null ];
    }
};

// doJobs() returns a promise
doJobs().then( ( result ) => {
   console.log( 'success:', result );
} )
.catch( ( error ) => {
    console.log( 'error:', error );
} );

// normal flow
console.log( 'I am a sync operation!' );