javascript - 需要合并具有相同键但不同值的对象

Question

我想找到最短和最漂亮的方法来转换具有相同类别键值的对象数组:

[{
  "label": "Apple",
  "category": "Fruits"
}, {
  "label": "Orange",
  "category": "Fruits"
}, {
  "label": "Potato",
  "category": "Vegetables"
}, {
  "label": "Tomato",
  "category": "Vegetables"
}, {
  "label": "Cherry",
  "category": "Berries"
}]

到具有来自同一类别的分组标签的标签:

[{
  "label": ["Apple", "Orange"],
  "category": "Fruits"
}, {
  "label": ["Potato", "Tomato"],
  "category": "Vegetables"
}, {
  "label": ["Cherry"],
  "category": "Berries"
}]

Answer 1

您可以使用一个对象作为哈希表并对类别进行分组。

var data = [{ "label": "Apple", "category": "Fruits" }, { "label": "Orange", "category": "Fruits" }, { "label": "Potato", "category": "Vegetables" }, { "label": "Tomato", "category": "Vegetables" }, { "label": "Cherry", "category": "Berries" }],
    grouped = [];

data.forEach(function (a) {
    if (!this[a.category]) {
        this[a.category] = { label: [], category: a.category };
        grouped.push(this[a.category]);
    }
    this[a.category].label.push(a.label);
}, Object.create(null));

console.log(grouped);

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