更好的做法：消除嵌套循環？

Question

我正在遍歷像這樣的一些對象（使用Underscore.js）：

      _.each(obj.Things, function(thing) {
        _.each(thing.SubThings, function(subThing) {
          _.each(subThing.SubSubThing, function(subSubThing) {
            things.push(subSubThing);
          });
        });
      });

從架構上來說，我不喜歡它的外觀。 有沒有一種更清潔的方式來完成這樣的任務？

Answer 1

提高代碼可讀性的一種方法是取消嵌套調用並僅使用常規函數調用。

_.each(obj.Things, processThing);

function processThing(thing) {
    _.each(thing.SubThings, processSubThing);
}

function processSubThing(subThing) {
    _.each(subThing.SubSubThing, processSubSubThing);
}

function processSubSubThin(subSubThing) {
    things.push(subSubThing);
}

如果使用ES6 / ES2015，則可以使用箭頭功能

let processThing = thing => _.each(thing.SubThings, processSubThing);

let processSubThing = subThing => _.each(subThing.SubSubThing, processSubSubThing);

let processSubSubThin = subSubThing => things.push(subSubThing);

_.each(obj.Things, processThing);

Answer 2

所有對象都是數組嗎？

然后，這有意義嗎？

var things = _.flatten(_.map(obj.Things, function(thing) {
    return _.pluck(thing.SubThings, "SubSubThings");
}));

如果您不想創建新事物。

things.push(_.map(obj.Things, function(thing) {
  return _.pluck(thing.SubThings, "SubSubThings");
}));
things = _.flatten(things);

Answer 3

使用Array.prototype.map和Array.prototype.reduce ，存在一種足夠表達的解決方案：

var things = obj.Things.map(function (thing) {
    return thing.SubThings;
}).reduce(function (things, subthing) {
    return things.concat(subthing.SubSubThings);
}, []);