SOURCE

const {
    merge,
    cloneDeep,
    isPlainObject,
    defaultsDeep,
    mergeWith,
  	difference,
  	keys,
  	omit
} = _;
const getType = val => Object.prototype.toString.call(val);
const customizer = (objValue, srcValue) => {
    // 类型相等且都为对象，保留对象中已存在的属性值执行合并
    if (isPlainObject(srcValue) && isPlainObject(objValue)) {
        return defaultsDeep(objValue, srcValue);
    }
    // 类型相等且不为对象，直接使用原始值
    else if (getType(objValue) === getType(srcValue)) {
        return objValue;
    }
    // 类型不相等，使用新属性值
    else {
        return srcValue;
    }
};

 
const oldObj = { border: {borderWidth: 1, posi: 11}, 'b': [2], fonta: 1};
const newObj = {border: {borderWidth: 4, borderColor: 'red'}, 'b': [4], fontSize: 1213};

const needKeys = keys(newObj);
const result = mergeWith(oldObj, newObj, customizer);
const newKeys = keys(result);
console.log(difference(needKeys, newKeys));
const data = omit(result, difference(newKeys, needKeys));

console.log(data);