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2018-07-26
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摘要：本篇Node.js教程探讨了如何在Node.js中合并两个复杂对象，希望阅读本篇文章以后大家有所收获，帮助大家对Node.js的理解更加深入。
本篇Node.js教程探讨了如何在Node.js中合并两个复杂对象，希望阅读本篇文章以后大家有所收获，帮助大家对Node.js的理解更加深入。
通常情况下，在Node.js中我们可以通过underscore的extend或者lodash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underscore或者lodash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<l; x++) {
def[i].push(newobjs[x]);
}
}
else {
for(var x=0; x < obj[i].length; x++)
{
var idxObj = obj[i][x];
if(def[i].indexOf(idxObj) === -1) {
def[i].push(idxObj);
}
}
}
}
else
{
def[i] = obj[i];
}
}
return def;}
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<l; x++) {
def[i].push(newobjs[x]);
}
}
else {
for(var x=0; x < obj[i].length; x++)
{
var idxObj = obj[i][x];
if(def[i].indexOf(idxObj) === -1) {
def[i].push(idxObj);
}
}
}
}
else
{
if (isNaN(obj[i]) || i.indexOf('_key') > -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
}
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