packages/core/src/utils/getSourceList.js
function getSourceList(playlist) {
  return (playlist || []).map((_, i) => getTrackSources(playlist, i)[0].src);
}
function getSourceList(playlist) {
  return (playlist || []).map((_, i) => getTrackSources(playlist, i)[0].src);
}
function getSourceList ( playlist ) { return ( playlist || [ ] ) . map ( ( _ , i ) => getTrackSources ( playlist , i ) [ 0 ] . src ) ; }
collapses playlist into flat list containing the first source url for each track
collapses playlist into flat list containing the first source url for each track