adsk-forge-LevelSectionPanel-step5

getRemoteLevels() {
    return new Promise(( resolve, reject ) => {
        const srvUrl = getServerUrl();
        fetch( `${ srvUrl }/api/levels`, {
            method: 'get',
            headers: new Headers({ 'Content-Type': 'application/json' })
        })
            .then( ( response ) => {
                if( response.status === 200 ) {
                    return response.json();
                } else {
                    return reject( new Error( response.statusText ) );
                }
            })
            .then( ( data ) => {
                if( !data ) return reject( new Error( 'Failed to fetch levels from the server' ) );

                return resolve( data );
            })
            .catch( ( error ) => reject( new Error( error ) ) ); });
}