[英]GroupBy Object Array JavaScript
我有一个输入:
var modbusData = [
{ Type: "rtu", IdDevice: "1", Time: "11:01:00", Data: "1,12,23" },
{ Type: "tcp", IdDevice: "2", Time: "11:01:11", Data: "30,40,50" },
{ Type: "rtu", IdDevice: "1", Time: "11:02:00", Data: "5,10,21" },
{ Type: "tcp", IdDevice: "2", Time: "11:02:11", Data: "32,44,53" },
];
我打电话后:
function groupBy(objectArray, property) {
return objectArray.reduce(function (acc, obj) {
let key = obj[property]
if (!acc[key]) {
acc[key] = []
}
acc[key].push(obj)
return acc
}, {})
}
let groupedData = groupBy(modbusData, 'Type')
console.log(groupedData)
结果将是:
{
rtu: [
{ Type: 'rtu', IdDevice: '1', Time: '11:01:00', Data: '1,12,23' },
{ Type: 'rtu', IdDevice: '1', Time: '11:02:00', Data: '5,10,21' }
],
tcp: [
{ Type: 'tcp', IdDevice: '2', Time: '11:01:11', Data: '30,40,50' },
{ Type: 'tcp', IdDevice: '2', Time: '11:02:11', Data: '32,44,53' }
]
}
现在我想要当modbusData 中没有 "Type" : "rtu" 或 "tcp" 时,结果将返回一个空数组,如下所示:
{
rtu: [
{ Type: 'rtu', IdDevice: '1', Time: '11:01:00', Data: '1,12,23' },
{ Type: 'rtu', IdDevice: '1', Time: '11:02:00', Data: '5,10,21' }
],
tcp: []
}
尝试使用扩展运算alltypes
并所有alltypes
let alltypes = { rtu: [], tcp: [] }
let result = {...alltypes, ...groupedData}
var modbusData = [ { Type: "rtu", IdDevice: "1", Time: "11:01:00", Data: "1,12,23" }, { Type: "rtu", IdDevice: "1", Time: "11:02:00", Data: "5,10,21" }, ]; function groupBy(objectArray, property) { return objectArray.reduce(function (acc, obj) { let key = obj[property] if (!acc[key]) { acc[key] = [] } acc[key].push(obj) return acc }, {}) } let groupedData = groupBy(modbusData, 'Type') let alltypes = { rtu: [], tcp: [] } let result = {...alltypes, ...groupedData} console.log(result)
您需要将预期的组键作为减速器的初级对象传递。
>>> [ 'rtu', 'tcp' ]
<<< Object.fromEntries(expectedGroups.map(k => [k, []])) // { rtu: [], tcp: [] }
var modbusData = [ { Type: "rtu", IdDevice: "1", Time: "11:01:00", Data: "1,12,23" }, { Type: "rtu", IdDevice: "1", Time: "11:02:00", Data: "5,10,21" } ]; function groupBy(objectArray, property, expectedGroups = []) { return objectArray.reduce(function (acc, obj) { let key = obj[property] if (!acc[key]) { acc[key] = [] } acc[key].push(obj) return acc }, Object.fromEntries(expectedGroups.map(k => [k, []]))) }; let groupedData = groupBy(modbusData, 'Type', [ 'rtu', 'tcp' ]); console.log(groupedData);
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这是一个使用 ES5/6 结构的更精简的版本。
const modbusData = [ { Type: "rtu", IdDevice: "1", Time: "11:01:00", Data: "1,12,23" }, { Type: "rtu", IdDevice: "1", Time: "11:02:00", Data: "5,10,21" } ]; const groupBy = (arr, prop, requiredKeys = []) => arr.reduce((acc, obj) => ({ ...acc, [obj[prop]]: [...(acc[obj[prop]] ?? []), obj] }), Object.fromEntries(requiredKeys.map(k => [k, []]))); const groupedData = groupBy(modbusData, 'Type', [ 'rtu', 'tcp' ]); console.log(groupedData);
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