SOURCE

const entry = {
a: {
 b: {
   c: {
     dd: 'abcdd'
   }
 },
 d: {
   xx: 'adxx'
 },
 e: 'ae'
}
}

// 要求转换成如下对象
// var output = {
// 'a.b.c.dd': 'abcdd',
// 'a.d.xx': 'adxx',
// 'a.e': 'ae'
// }

//递归
function flatObj( obj, parentKey= '', result= {}) {
    Object.keys(obj).forEach(key => {
        let increasedKey = parentKey == "" ? `${parentKey}${key}` :`${parentKey}.${key}`
        if( typeof obj[key]  == "object") {
            flatObj(obj[key], increasedKey, result)
        }else {
            result[increasedKey] = obj[key]
        }
    })
    return result
}
const output = flatObj(entry)

Object.keys(output).forEach(key => {
    console.log(key+':'+output[key])
})