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'
}
]
}
我喜欢写它没有依赖/复杂性,只是纯粹的简单js。
const mp = {}
const cars = [
{
model: 'Imaginary space craft SpaceX model',
year: '2025'
},
{
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'
}
]
cars.forEach(c => {
if (!c.make) return // exit (maybe add them to a "no_make" category)
if (!mp[c.make]) mp[c.make] = [{ model: c.model, year: c.year }]
else mp[c.make].push({ model: c.model, year: c.year })
})
console.log(mp)
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));
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);
@metakungfu answer略有不同,主要区别在于它从结果对象中省略了原始键,因为在某些情况下对象本身不再需要它,因为它现在在父对象中可用。
const groupBy = (_k, a) => a.reduce((r, {[_k]:k, ...p}) => ({
...r, ...{[k]: (
r[k] ? [...r[k], {...p}] : [{...p}]
)}
}), {});
考虑到您的原始输入对象:
console.log(groupBy('make', cars));
会导致:
{
audi: [
{ model: 'r8', year: '2012' },
{ model: 'rs5', year: '2013' }
],
ford: [
{ model: 'mustang', year: '2012' },
{ model: 'fusion', year: '2015' }
],
kia: [
{ model: 'optima', year: '2012' }
]
}