有人知道一种方法(lodash如果可能的话)通过对象键分组对象数组，然后根据分组创建一个新的对象数组吗?例如，我有一个汽车对象数组:
const cars = [
{
'make': 'audi',
'model': 'r8',
'year': '2012'
}, {
'make': 'audi',
'model': 'rs5',
'year': '2013'
}, {
'make': 'ford',
'model': 'mustang',
'year': '2012'
}, {
'make': 'ford',
'model': 'fusion',
'year': '2015'
}, {
'make': 'kia',
'model': 'optima',
'year': '2012'
},
];
我想创建一个新的汽车对象数组，由make分组:
const cars = {
'audi': [
{
'model': 'r8',
'year': '2012'
}, {
'model': 'rs5',
'year': '2013'
},
],
'ford': [
{
'model': 'mustang',
'year': '2012'
}, {
'model': 'fusion',
'year': '2015'
}
],
'kia': [
{
'model': 'optima',
'year': '2012'
}
]
}
这是一个通用函数，将返回Array groupBy自己的键。
const getSectionListGroupedByKey = < T > (
property: keyof T,
List: Array < T >
): Array < {
title: T[keyof T];data: Array < T >
} > => {
const sectionList: Array < {
title: T[keyof T];data: Array < T >
} > = [];
if (!property || !List ? .[0] ? .[property]) {
return [];
}
const groupedTxnListMap: Map < T[keyof T], Array < T >> = List.reduce((acc, cv) => {
const keyValue: T[keyof T] = cv[property];
if (acc.has(keyValue)) {
acc.get(keyValue) ? .push(cv);
} else {
acc.set(keyValue, [cv]);
}
return acc;
}, new Map < T[keyof T], Array < T >> ());
groupedTxnListMap.forEach((value, key) => {
sectionList.push({
title: key,
data: value
});
});
return sectionList;
};
// Example
const cars = [{
'make': 'audi',
'model': 'r8',
'year': '2012'
}, {
'make': 'audi',
'model': 'rs5',
'year': '2013'
}, {
'make': 'ford',
'model': 'mustang',
'year': '2012'
}, {
'make': 'ford',
'model': 'fusion',
'year': '2015'
}, {
'make': 'kia',
'model': 'optima',
'year': '2012'
}, ];
const result = getSectionListGroupedByKey('make', cars);
console.log('result: ', result)
您正在寻找_.groupBy()。
如果需要，从对象中删除分组的属性应该很简单:
Const cars = [{
“做”:“奥迪”,
“模型”:“r8”,
“年”:“2012”
},{
“做”:“奥迪”,
“模型”:“生活费”,
“年”:“2013”
},{
“做”:“福特”,
“模型”:“野马”,
“年”:“2012”
},{
“做”:“福特”,
“模型”:“融合”,
“年”:“2015”
},{
“做”:“克钦独立军”,
“模型”:“最佳状态”,
“年”:“2012”
});
Const分组= _。groupBy(cars, car => car.make);
console.log(分组);
< script src = " https://cdn.jsdelivr.net/lodash/4.17.2/lodash.min.js " > < /脚本>
我用REAL GROUP BY作为JS数组的例子和这个任务完全一样
const inputArray = [
{ Phase: "Phase 1", Step: "Step 1", Task: "Task 1", Value: "5" },
{ Phase: "Phase 1", Step: "Step 1", Task: "Task 2", Value: "10" },
{ Phase: "Phase 1", Step: "Step 2", Task: "Task 1", Value: "15" },
{ Phase: "Phase 1", Step: "Step 2", Task: "Task 2", Value: "20" },
{ Phase: "Phase 2", Step: "Step 1", Task: "Task 1", Value: "25" },
{ Phase: "Phase 2", Step: "Step 1", Task: "Task 2", Value: "30" },
{ Phase: "Phase 2", Step: "Step 2", Task: "Task 1", Value: "35" },
{ Phase: "Phase 2", Step: "Step 2", Task: "Task 2", Value: "40" }
];
var outObject = inputArray.reduce(function(a, e) {
// GROUP BY estimated key (estKey), well, may be a just plain key
// a -- Accumulator result object
// e -- sequentally checked Element, the Element that is tested just at this itaration
// new grouping name may be calculated, but must be based on real value of real field
let estKey = (e['Phase']);
(a[estKey] ? a[estKey] : (a[estKey] = null || [])).push(e);
return a;
}, {});
console.log(outObject);
使用lodash/fp，你可以使用_.flow()创建一个函数，它首先按键分组，然后映射每个组，并从每个项中省略一个键:
const { flow, groupBy, mapValues, map, omit } = _;
const groupAndOmitBy = key => flow(
groupBy(key),
mapValues(map(omit(key)))
);
const cars = [{ make: 'audi', model: 'r8', year: '2012' }, { make: 'audi', model: 'rs5', year: '2013' }, { make: 'ford', model: 'mustang', year: '2012' }, { make: 'ford', model: 'fusion', year: '2015' }, { make: 'kia', model: 'optima', year: '2012' }];
const groupAndOmitMake = groupAndOmitBy('make');
const result = groupAndOmitMake(cars);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }
<script src='https://cdn.jsdelivr.net/g/lodash@4(lodash.min.js+lodash.fp.min.js)'></script>
