将拍平对象转换为层级对象，以点分割生成新的对象（默认不会出现嵌套情况），相同父级需要做归并处理。

Question

JavaScript
// 初始值

{

    'a.b.c': 1,

    'a.d': 2,

    'e' : 3

}

// 最终值

{

    a: {

        b: {

            c: 1    

        },

        d: 2,

    },

    e: 3

}

Answer 1

var prop2obj = prop => Object.keys(prop).reduce((res,key) => {
    key.split('.').reduce((obj, k, i, arr) => obj[k] = i == arr.length-1 ? prop[key] : (obj[k] || {}), res);
    return res;
}, {});

prop2obj({

'a.b.c': 1,

'a.d': 2,

'e' : 3

})

Answer 2

function makeObj (input = {}) {
    const output = {};

    for (const [path, value] of Object.entries(input)) {
        let target = output;
        let key = "";
        for (const char of path) {
            switch (char) {
            case ".":
                target = target[key] ?? (target[key] = {});
                key = "";
                break;
            default:
                key += char;
            }
        }
        target[key] = value;
    }

    return output;
}