下划线组和排序嵌套数组

Question

使用流星，我得到了一个mongo聚合，返回一个反应性变量，如下所示：

[{
"_id": "game1",
"playerpicks": [
  {
    "player": "Chris",
    "pick": "atsa"
  },
  {
    "player": "al",
    "pick": "suh"
  },
  {
    "player": "al",
    "pick": "atsh"
  },
  {
    "player": "Chris",
    "pick": "sua"
  }]  },{
"_id": "game2",
"playerpicks": [
  {
    "player": "al",
    "pick": "atsa"
  },
  {
    "player": "Chris",
    "pick": "suh"
  },
  {
    "player": "Chris",
    "pick": "atsh"
  },
  {
    "player": "al",
    "pick": "sua"
  }]  },  ....  ]

我需要将这些数据转换成一个网格，理想情况如下：

GAME       al          Chris
game1    suh/atsh      sua/atsa
game2    sua/atsa      suh/atsh

假设这是一个很大的挑战，我可以这样做：

game 1    al: suh/atsh     Chris:  sua/atsa
game 2    al: sua/atsa     Chris:  suh/atsh

我看到Mongo需要排序才能在客户端进行排序，所以我专注于使用下划线，但即使在嵌套数组“播放者选择”的_.sortBy或_.groupBy的初始步骤中也无法获得任何结果。

我的尝试如下：

_.each(monArr, function(obj){ _.each(obj.playerpicks, function(nst){ _.groupBy( nst.player ) }) })

以及：

_.groupBy(monArr, function(obj){return obj.playerpicks.player})

但我离得太远了。没有返回数据。任何建议都非常感谢

Answer 1

下面是一种使用大量下划线函数的解决方案，将其分解为离散块，希望能使其更加可读性：

// helper function to combine a player's picks into a string delimited by '/'
let combinePicks = player => _.pluck(player, 'pick').join('/');

// helper function to group a game by a player
let groupGame = game => _.chain(game.playerpicks)
    .groupBy('player')
    .mapObject(combinePicks)
    .value();

// map the data to create the object in the required form
let result = _.map(data, game => _.extend({GAME: game._id}, groupGame(game) ));

对于不支持mapObject (Pre1.8)的较早版本的下划线，可以使用result实现相同的结果：

let combinePicks = function(memo, player, key){
    memo[key] = _.pluck(player, 'pick').join('/');
    return memo;
} 

let groupGame = game => _.chain(game.playerpicks)
    .groupBy('player')
    .reduce(combinePicks, {})
    .value();

​

		var data = [{
"_id": "game1",
"playerpicks": [
  {
    "player": "Chris",
    "pick": "atsa"
  },
  {
    "player": "al",
    "pick": "suh"
  },
  {
    "player": "al",
    "pick": "atsh"
  },
  {
    "player": "Chris",
    "pick": "sua"
  }]  },{
"_id": "game2",
"playerpicks": [
  {
    "player": "al",
    "pick": "atsa"
  },
  {
    "player": "Chris",
    "pick": "suh"
  },
  {
    "player": "Chris",
    "pick": "atsh"
  },
  {
    "player": "al",
    "pick": "sua"
  }]  }
	];

	let combinePicks = player => _.pluck(player, 'pick').join('/');

	let groupGame = game => _.chain(game.playerpicks)
		.groupBy('player')
		.mapObject(combinePicks)
		.value();
	
	let result = _.map(data, game => _.extend({GAME: game._id}, groupGame(game) ));


document.getElementById('result').textContent = JSON.stringify(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

<p>
  <pre id="result"></pre>
</p>

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