通常情况下，在Node.js中我们可以通过的extend或者的merge来合并两个对象，但是对于像下面这种复杂的对象，要如何来应对呢？
例如我有以下两个object：
var obj1 = { "name" : "myname", "status" : 0, "profile": { "sex":"m", "isactive" : true}, "strarr":["one", "three"], "objarray": [ { "id": 1, "email": "a1@me.com", "isactive":true }, { "id": 2, "email": "a2@me.com", "isactive":false } ]};var obj2 = { "name" : "myname", "status" : 1, "newfield": 1, "profile": { "isactive" : false, "city": "new York"}, "strarr":["two"], "objarray": [ { "id": 1, "isactive":false }, { "id": 2, "email": "a2modified@me.com" }, { "id": 3, "email": "a3new@me.com", "isactive" : true } ]}; 希望合并之后的结果输出成下面这样：
{ name: 'myname', status: 1, profile: { sex: 'm', isactive: false, city: 'new York' }, strarr: [ 'one', 'three', 'two' ], objarray: [ { id: 1, email: 'a1@me.com', isactive: false }, { id: 2, email: 'a2modified@me.com', isactive: false }, { id: 3, email: 'a3new@me.com', isactive: true } ],newfield: 1 } 通过或者现有的方法我们无法实现上述结果，那只能自己写代码来实现了。
function mergeObjs(def, obj) { if (!obj) { return def; } else if (!def) { return obj; } for (var i in obj) { // if its an object if (obj[i] != null && obj[i].constructor == Object) { def[i] = mergeObjs(def[i], obj[i]); } // if its an array, simple values need to be joined. Object values need to be remerged. else if(obj[i] != null && (obj[i] instanceof Array) && obj[i].length > 0) { // test to see if the first element is an object or not so we know the type of array we're dealing with. if(obj[i][0].constructor == Object) { var newobjs = []; // create an index of all the existing object IDs for quick access. There is no way to know how many items will be in the arrays. var objids = {} for(var x= 0, l= def[i].length ; x < l; x++ ) { objids[def[i][x].id] = x; } // now walk through the objects in the new array // if the ID exists, then merge the objects. // if the ID does not exist, push to the end of the def array for(var x= 0, l= obj[i].length; x < l; x++) { var newobj = obj[i][x]; if(objids[newobj.id] !== undefined) { def[i][x] = mergeObjs(def[i][x],newobj); } else { newobjs.push(newobj); } } for(var x= 0, l = newobjs.length; x 将上述代码稍作改进，我们可以实现在合并过程中将Number类型的值自动相加。
function merge(def, obj) { if (!obj) { return def; } else if (!def) { return obj; } for (var i in obj) { // if its an object if (obj[i] != null && obj[i].constructor == Object) { def[i] = merge(def[i], obj[i]); } // if its an array, simple values need to be joined. Object values need to be re-merged. else if(obj[i] != null && (obj[i] instanceof Array) && obj[i].length > 0) { // test to see if the first element is an object or not so we know the type of array we're dealing with. if(obj[i][0].constructor == Object) { var newobjs = []; // create an index of all the existing object IDs for quick access. There is no way to know how many items will be in the arrays. var objids = {} for(var x= 0, l= def[i].length ; x < l; x++ ) { objids[def[i][x].id] = x; } // now walk through the objects in the new array // if the ID exists, then merge the objects. // if the ID does not exist, push to the end of the def array for(var x= 0, l= obj[i].length; x < l; x++) { var newobj = obj[i][x]; if(objids[newobj.id] !== undefined) { def[i][x] = merge(def[i][x],newobj); } else { newobjs.push(newobj); } } for(var x= 0, l = newobjs.length; x -1){ def[i] = obj[i]; } else{ def[i] += obj[i]; } } } return def;} 例如有以下两个对象：
var data1 = { "_id" : "577327c544bd90be508b46cc", "channelId_info" : [ { "channelId_key" : "0", "secondLevel_group" : [ { "secondLevel_key" : "568cc36c44bd90625a045c60", "sender_group" : [ { "sender_key" : "577327c544bd90be508b46cd", "sender_sum" : 40.0 } ], "senders_sum" : 40.0 } ], "channelId_sum" : 40.0 } ], "car_sum" : 40.0};var data2 = { "_id" : "577327c544bd90be508b46cc", "channelId_info" : [ { "channelId_key" : "0", "secondLevel_group" : [ { "secondLevel_key" : "568cc36c44bd90625a045c60", "sender_group" : [ { "sender_key" : "577327c544bd90be508b46cd", "sender_sum" : 20.0 }, { "sender_key" : "5710bcc7e66620fd4bc0914f", "sender_sum" : 5.0 } ], "senders_sum" : 25.0 }, { "secondLevel_key" : "55fbeb4744bd9090708b4567", "sender_group" : [ { "sender_key" : "5670f993a2f5dbf12e73b763", "sender_sum" : 10.0 } ], "senders_sum" : 10.0 } ], "channelId_sum" : 35.0 }, { "channelId_key" : "1", "secondLevel_group" : [ { "secondLevel_key" : "568cc36c44bd90625a045c60", "sender_group" : [ { "sender_key" : "577327c544bd90be508b46cd", "sender_sum" : 20.0 } ], "senders_sum" : 20.0 } ], "channelId_sum" : 20.0 } ], "car_sum" : 55.0}; 合并之后的结果如下：
{ "_id": "577327c544bd90be508b46cc", "channelId_info": [ { "channelId_key": "0", "secondLevel_group": [ { "secondLevel_key": "568cc36c44bd90625a045c60", "sender_group": [ { "sender_key": "577327c544bd90be508b46cd", "sender_sum": 60 }, { "sender_key": "5710bcc7e66620fd4bc0914f", "sender_sum": 5 } ], "senders_sum": 65 }, { "secondLevel_key": "55fbeb4744bd9090708b4567", "sender_group": [ { "sender_key": "5670f993a2f5dbf12e73b763", "sender_sum": 10 } ], "senders_sum": 10 } ], "channelId_sum": 75 }, { "channelId_key": "1", "secondLevel_group": [ { "secondLevel_key": "568cc36c44bd90625a045c60", "sender_group": [ { "sender_key": "577327c544bd90be508b46cd", "sender_sum": 20 } ], "senders_sum": 20 } ], "channelId_sum": 20 } ], "car_sum": 95} 上述代码在日常工作中很有用，值得收藏！