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angularjs$q。全部用于嵌套承诺

angular-promise angularjs

wivku · 技术社区 · 7 年前

$q.all

如何修改下面的示例,以便在完成所有请求后执行代码?

// foreach series --> load series details & seasons, foreach season --> load episodes
// when all requests are completed: do something

var requests = []

// e.g. series = [1]
series.forEach(function(seriesId) {
    requests.push(loadSeriesDetails(seriesId).then(function(data) {
        console.log("received details for series "+seriesId)
        // e.g. {id:1, title:"show 1"}
    }))
    requests.push(loadSeasons(seriesId).then(function (data) {
        console.log("received seasons for series "+seriesId+": ", data.seasons.length)
        // e.g. [{id:11, title:"season 1"}, {id:12, title:"season 2"}]
        data.seasons.map(function(e) {return e.id}).forEach(function(seasonId) {
            requests.push(loadEpisodes(seasonId).then(function (data) {
                console.log("received episodes for season "+seasonId+": ", data.episodes.length)
                // e.g.
                // season 11: [{id:111, title:"episode 1-1-1"}, {id:112, title:"episode 1-1-2"}, {id:113, title:"episode 1-1-3"}]
                // season 12: [{id:121, title:"episode 1-2-1"}, {id:122, title:"episode 1-2-2"}]
            }))
        })
    }))
})

$q.all(requests).then(function(result) {
    console.log("*** all requests completed ***")
    console.log(result.length)
})

上述示例将返回2(1x loadSeriesDetails loadSeasons )而不是4(1x LoadSeries详细信息 ,1x loadEpisodes ).

建议?提前感谢!

loadSeriesDetails = function(id) {
  url = "..."+id

  return $http.get(url).then(
    function (result) {
      return result.data
    }, function (error) {
      Ì¶rÌ¶eÌ¶tÌ¶uÌ¶rÌ¶nÌ¶ Ì¶eÌ¶rÌ¶rÌ¶oÌ¶rÌ¶ 
      throw error;
  });
}

2 回复 | 直到 7 年前

wivku 7 年前

Frank's answer

// foreach series --> load series details & seasons, foreach season --> load episodes
// when all requests are completed: do something

var requests = []

// e.g. series = [1]
series.forEach(function(seriesId) {
    requests.push(loadSeriesDetails(seriesId).then(function(data) {
        console.log("received details for series "+seriesId)
        // e.g. {id:1, title:"show 1"}
    }))
    requests.push(loadSeasons(seriesId).then(function (data) {
        console.log("received seasons for series "+seriesId+": ", data.seasons.length)
        // e.g. [{id:11, title:"season 1"}, {id:12, title:"season 2"}]
        var innerRequests = [] // <<<==============
        data.seasons.map(function(e) {return e.id}).forEach(function(seasonId) {
            innerRequests.push(loadEpisodes(seasonId).then(function (data) {
                console.log("received episodes for season "+seasonId+": ", data.episodes.length)
                // e.g.
                // season 11: [{id:111, title:"episode 1-1-1"}, {id:112, title:"episode 1-1-2"}, {id:113, title:"episode 1-1-3"}]
                // season 12: [{id:121, title:"episode 1-2-1"}, {id:122, title:"episode 1-2-2"}]
            }))
        })
        return $q.all(innerRequests) //  <<<==============
    }))
})

$q.all(requests).then(function(result) {
    console.log("*** all requests completed ***")
    console.log(result.length)
})

georgeawg 7 年前

你的 requests 数组应该具有在将其传递给时需要解决的所有承诺 $q.all .目前,您正在添加您的承诺 loadEpisodes 到 请求

您可以将其分解,以便内部部分返回自己的部分 $.q.all

    var requests = [];

    series.forEach(function (seriesId) {
        requests.push(loadSeriesDetails(seriesId).then(function (data) {
            console.log("received details for series " + seriesId);
            return data;
        }));

        requests.push(loadSeasons(seriesId).then(function (data) {
            console.log("received seasons for series " + seriesId + ": ", data.seasons.length);
            return loadAllEpisodes(data.seasons);
        }));
    });

    function loadAllEpisodes(seasons) {
        var requests = seasons.map(function (season) {
            return loadEpisodes(season.id).then(function (data) {
                console.log("received episodes for season " + season.id + ": ", data.episodes.length);
                return data;
            });
        });

        return $q.all(requests);
    }

    q.all(requests).then(function(result) {
        console.log("*** all requests completed ***");
        console.log(result.length);
    });

$q.all ,因为你正在从每条链的最后承诺中获得结果。因此,您可能需要调整返回语句,使其按您需要的方式对信息进行分组。