lodash - lodash-对数组进行分组和填充

Question

使用lodash，如何将生日相同的人的姓名归为一组，如下所示？

我使用嵌套的for循环写出了这个信息，但我想在lodash中会有一种更优雅的方法。我没有使用太多，并试图找出要使用的功能。

[
    { "birthdate": "1993", "name": "Ben" },
    { "birthdate": "1994", "name": "John" },
    { "birthdate": "1995", "name": "Larry" },
    { "birthdate": "1995", "name": "Nicole" },
    { "birthdate": "1996", "name": "Jane" },
    { "birthdate": "1996", "name": "Janet" },
    { "birthdate": "1996", "name": "Dora" },
]

到

[
    { "birthdate": "1993", "names": [ "Ben" ] }, 
    { "birthdate": "1994", "names": [ "John"] },
    { "birthdate": "1995", "names": [ "Larry", "Nicole" ] }, 
    { "birthdate": "1996", "names": [ "Jane", "Janet", "Dora" ] }        
]

Answer 1

您可以使用groupBy()通过birthdate对集合中的每个项目进行分组。将项目分组后，可以使用map()迭代每个组，并将它们形成为包括birthdate和names的新格式。要从分组的项目中获取名称数组，可以再次使用map()函数返回所有name值。

var result = _(source)
    .groupBy('birthdate')
    .map(function(items, bdate) {
      return {
        birthdate: bdate,
        names: _.map(items, 'name')
      };
    }).value();

var source = [
    { "birthdate": "1993", "name": "Ben" },
    { "birthdate": "1994", "name": "John" },
    { "birthdate": "1995", "name": "Larry" },
    { "birthdate": "1995", "name": "Nicole" },
    { "birthdate": "1996", "name": "Jane" },
    { "birthdate": "1996", "name": "Janet" },
    { "birthdate": "1996", "name": "Dora" },
];
  
var result = _(source)
    .groupBy('birthdate')
    .map(function(items, bdate) {
      return {
        birthdate: bdate,
        names: _.map(items, 'name')
      };
    }).value();

document.body.innerHTML = '<pre>' + JSON.stringify(result, 0, 4) + '</pre>';

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