js 合并 属性值相同的项

let a = [{
    "driverName": "apple",
    "description": "1",
},, {
    "driverName": "banana",
    "description": "1",
} {
    "driverName": "pants",
    "description": "2",
}, {
    "driverName": "coat",
    "description": "2",
}]
// 将上述数组a中descrition相同的对象合并成一个children，期望得到：
[{
    description: "1",
    children: [{
        driverName: "apple"
        description: "1"
    },{
        driverName: "banana"
        description: "1"
    }]
},{
    description: "2",
    children: [{
        driverName: "coat"
        description: "2"
    },{
        driverName: "pants"
        description: "2"
    }]
}]

 // 数组中descrition相同的对象合并成一个children
let b = []
a.forEach((item, index) => {
    let flag = true
    b.forEach((item2, index2) => {
        if (item.description === item2.description) {
            flag = false
            b[index2].children.push(item)
        }
    })
    if (flag) {
        b.push({
            description: item.description,
            children: [item]
        })
    }
})
 
console.log(b)