jquery如何循环get后将请求到的json合并

api_domain = ***,
search = {
    artist: api_domain + 'search/musician',
    music: api_domain + 'search/music',
    playlist: api_domain + 'search/playlist',
  }

function search(keyword) {
  $.when(
    $.get(api.search.music, {
      'keyword': keyword,
      'page': 1,
      'page_count': 20,
    }),
    $.get(api.search.artist, {
      'keyword': keyword,
      'page': 1,
      'page_count': 20,
    }),
    $.get(api.search.playlist, {
      'keyword': keyword,
      'page': 1,
      'page_count': 20,
    })
  ).done(function(music, artist, playlist) {
    var data = new Object
    $.extend(true, data, music[0], artist[0], playlist[0]);
    console.log(data);
  })