对 JavaScript 数组进行分组
javascriptweb developmentfront end technologyobject oriented programming
假设，我们有一个像这样的 JavaScript 数组 −
const data = [
{
&"dataId": &"1",
&"tableName": &"table1",
&"column": &"firstHeader",
&"rows": [
&"a&",&"b&",&"c&"
]
},
{
&"dataId&": &"2&",
&"tableName&": &"table1&",
&"column&": &"secondHeader&",
&"rows&": [
"d";, ]
}, {
&"dataId":&"3",
&"tableName":&"table2",
&"column":&"aNewFirstHeader",
&"rows":[
1,2,3
]
}
];
我们需要编写一个 JavaScript 函数，其中包含一个这样的数组。该函数应基于原始数组构造一个新的对象分组数组。
分组数组应包含单独的、唯一的"tableName"对象的数据，并将其放入自己的对象中。
因此，最终的输出应如下所示 −
const output = [
{
"tableName": "table1",
"column": ["firstHeader", "secondHeader"],
"rows": [["a","b","c"], ["d","e","f"]]
},
{
"tableName": "table2",
"column": ["aNewFirstHeader"],
"rows": [[1,2,3]]
}
];
示例
const arr = [
{
"dataId": "1",
"tableName": "table1",
"column": "firstHeader",
"rows": [ "val","b","c" ]
},
{
"dataId": "2",
"tableName": "table1",
"column": "secondHeader",
"rows": [
"d","e","f",
]
},
{
"dataId": "3",
"tableName": "table2",
"column": "aNewFirstHeader",
"rows": [
1,2,3
]
}
];
const groupArray = (arr = []) => {
const res = arr.reduce((obj => (acc, val) => {
let item = obj.get(val.tableName);
if (!item) {
item = {
tableName: val.tableName, column: [], rows: []
}
obj.set(val.tableName, item); acc.push(item);
};
item.column.push(val.column); item.rows.push(val.rows);
return acc;
})(new Map), []);
return res;
};
console.log(JSON.stringify(groupArray(arr), undefined, 4));
输出
控制台中的输出将是 −
[
{
"tableName": "table1",
"column":
[
"firstHeader",
"secondHeader"
],
"rows": [
[
"val", "b", "c"
],
[
"d", "e", "f"
]
]
}, {
"tableName": "table2",
"column": [
"aNewFirstHeader"
],
"rows": [
[
1, 2, 3
]
]
}
]
