Question

我有一个像这样的JSON文件：

[
  {
    "type": -1,
    "name": "First Group"
  },
  {
    "type": 2,
    "name": "A"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Second Group"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Third Group"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": 2,
    "name": "A"
  }
]

我想在许多阵列上划分这个对象数组，然后用＆＃34; type＆＃34;：-1 字段对它进行分组。

例如，对于当前的JSON，我希望得到类似的结果：

1）

[
  {
    "type": -1,
    "name": "First Group"
  },
  {
    "type": 2,
    "name": "A"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  }
]

2）

[
  {
    "type": -1,
    "name": "Second Group"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  }
]

3）

[
  {
    "type": -1,
    "name": "Third Group"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": 2,
    "name": "A"
  }
]

我的问题在下一个：

在TypeScript / JavaScript上是否存在某些功能？或者需要创建特定的东西。如果不存在，那么如何为此创建一个更好，更快的解决方案呢？

Answer 1

没有内置函数或方法来获取想要的组。

您可以为每个找到的type等于-1获取一个新数组，并为所有其他类型获取结果集的最后一个插入数组。

这显然仅适用于已排序的数组。

＆＃13;

var array = [{ type: -1, name: "First Group" }, { type: 2, name: "A" }, { type: 3, name: "B" }, { type: 4, name: "C" }, { type: -1, name: "Second Group" }, { type: 3, name: "B" }, { type: 4, name: "C" }, { type: -1, name: "Third Group" }, { type: 4, name: "C" }, { type: 2, name: "A" }],
    grouped = array.reduce(function (r, a) {
        if (a.type === -1) {
            r.push([a]);
        } else {
            r[r.length - 1].push(a);
        }
        return r;
    }, []);

console.log(grouped);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

Answer 2

const arr = [
	{
		"type": -1,
		"name": "First Group"
	},
	{
		"type": 2,
		"name": "A"
	},
	{
		"type": 3,
		"name": "B"
	},
	{
		"type": 4,
		"name": "C"
	},
	{
		"type": -1,
		"name": "Second Group"
	},
	{
		"type": 3,
		"name": "B"
	},
	{
		"type": 4,
		"name": "C"
	},
	{
		"type": -1,
		"name": "Third Group"
	},
	{
		"type": 4,
		"name": "C"
	},
	{
		"type": 2,
		"name": "A"
	}
];
const chunks = [];
let chunk = [];
arr.forEach((item) => {
	if(item.type === -1) {
		if(chunk.length) {
			chunks.push(chunk);
		}
		chunk = [];
	}
	chunk.push(item);
});
chunks.push(chunk);
console.log(chunks);

Answer 3

尝试遵循简单的逻辑。

var data = [
  {
    "type": -1,
    "name": "First Group"
  },
  {
    "type": 2,
    "name": "A"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Second Group"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Third Group"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": 2,
    "name": "A"
  }
];

var output = [],   
    _index = 0;
    
data.forEach(function(obj){        
    if(obj.type == -1){
      output.push([obj]);
      _index++;
    } else {
     output[_index-1].push(obj);
    }
});

console.log(output);

Answer 4

使用Array.prototype.reduce：

const collection = [{
    "type": -1,
    "name": "First Group"
  },
  {
    "type": 2,
    "name": "A"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Second Group"
  },
  {
    "type": 3,
    "name": "B"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": -1,
    "name": "Third Group"
  },
  {
    "type": 4,
    "name": "C"
  },
  {
    "type": 2,
    "name": "A"
  }
]

const makeReducerByTypeValue = value => (result, el, index) => {
  if (el.type === value) {
    result.sorted.push([])
    if (index > 0) result.currentIndex++
  }
  result.sorted[result.currentIndex].push(el)
  return result
}

const sorted = collection.reduce(makeReducerByTypeValue(-1), {
  currentIndex: 0,
  sorted: []
}).sorted

sorted.forEach(el => console.log(el))

JavaScript按字段划分对象数组

4 个答案: