自定分组

结果：

const people = [
    { name: 'Alice', age: 21 },
    { name: 'Max', age: 20 },
    { name: 'Jane', age: 20 }
];
/**
 * 
 * @param {*} objectArray  数组
 * @param {*} property   分组名称
 * @returns 
 */
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
    }, {})
}
 const groupedPeople = groupBy(people, 'age')
 console.log(groupedPeople)