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'
}
]
}
另一个解决方案:
Var汽车= [
{“使”:“奥迪”,“模型”:“r8”,“年”:“2012”},{“使”:“奥迪”,“模型”:“生活费”,“年”:“2013”},
{“使”:“福特”,“模型”:“野马”,“年”:“2012”},{“使”:“福特”,“模型”:“融合”,“年”:“2015”},
{'make': 'kia'，'model': 'optima'，'year': '2012'}，
];
const reducedCars =汽车。Reduce ((acc， {make, model, year}) => (
｛
acc,
[make]: acc[make] ?[…Acc [make]， {model, year}]: [{model, year}]，
｝
), {});
console.log (reducedCars);
对于key可以为null的情况，我们希望将它们分组为其他
var 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'},
{'make':'kia','model':'optima','year':'2033'},
{'make':null,'model':'zen','year':'2012'},
{'make':null,'model':'blue','year':'2017'},
];
result = cars.reduce(function (r, a) {
key = a.make || 'others';
r[key] = r[key] || [];
r[key].push(a);
return r;
}, Object.create(null));
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);
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