使用...或者Object.assign()等赋值方式只能进行浅层的对象赋值，如果对象存在多级嵌套，则无法进行合并更新，以下可以使用深度合并：

function mergeDeep(...objects) {
    const isObject = obj => obj && typeof obj === 'object';
    
    return objects.reduce((prev, obj) => {
      Object.keys(obj).forEach(key => {
        const pVal = prev[key];
        const oVal = obj[key];
        
        if (Array.isArray(pVal) && Array.isArray(oVal)) {
          prev[key] = pVal.concat(...oVal);
        }
        else if (isObject(pVal) && isObject(oVal)) {
          prev[key] = mergeDeep(pVal, oVal);
        }
        else {
          prev[key] = oVal;
        }
      });
      
      return prev;
    }, {});
  }
// copy from https://stackoverflow.com/questions/27936772/how-to-deep-merge-instead-of-shallow-merge

样例2：

MergeRecursive = (obj1, obj2) => {
    for (const key in obj2) {
        try {
            // Property in destination object set; update its value.
            if (obj2[key].constructor == Object) {
                obj1[key] = MergeRecursive(obj1[key], obj2[key]);
            } else {
                obj1[key] = obj2[key];
            }
        } catch (e) {
            // Property in destination object not set; create it and set its value.
            if (obj2[key]) {
                // If obj2[key] is undefined, the destination object will be undefined.
                // We shouldn't merge the undefined object to destination.
                obj1[key] = obj2[key];
            }
        }
    }

    return obj1;
}