Merge two javascript objects adding values of common properties
I have two or more javascript objects. I want to merge them adding values of common properties and then sort them in descending order of values.
eg
var a = {en : 5,fr: 3,in: 9}
var b = {en: 8,fr: 21,br: 8}
var c = merge(a,b)
c should then be like this:
c = {
fr: 24,
en: 13,
in:9,
br:8
}
ie both objects are merge, values of common keys are added and then keys are sorted.
Here's what I've tried:
var a = {en : 5,fr: 3,in: 9}
var b = {en: 8,fr: 21,br: 8}
c = {}
// copy common values and all values of a to c
for(var k in a){
if(typeof b[k] != 'undefined'){
c[k] = a[k] + b[k]
}
else{ c[k] = a[k]}
}
// copy remaining values of b (which were not common)
for(var k in b){
if(typeof c[k]== 'undefined'){
c[k] = b[k]
}
}
// Create a object array for sorting
var arr = [];
for(var k in c){
arr.push({lang:k,count:c[k]})
}
// Sort object array
arr.sort(function(a, b) {
return b.count - a.count;
})
but I dont think its good. So many loops :( It would be nice if someone can provide a less messy and good code.
无法对对象的属性进行排序，但可以对数组进行排序：
var merged = $.extend({}, a);
for (var prop in b) {
if (merged[prop]) merged[prop] += b[prop];
else merged[prop] = b[prop];
}
// Returning merged at this point will give you a merged object with properties summed, but not ordered.
var properties = [];
for (var prop in merged) {
properties.push({
name: prop,
value: merged[prop]
});
}
return properties.sort(function(nvp1, nvp2) {
return nvp1.value - nvp2.value;
});
EDIT - i modified the script, this merges the properties if they are of the same type: numbers are summed, strings are concatenated and objects are recursively merged. I didn't include sorting because (quoting this answer Sorting JavaScript Object by property value)
JavaScript objects are unordered by definition (see the ECMAScript Language Specification, section 8.6). The language specification doesn't even guarantee that, if you iterate over the properties of an object twice in succession, they'll come out in the same order the second time.
If you need things to be ordered, use an array and the Array.prototype.sort method.
function is_object(mixed_var) {
if (Object.prototype.toString.call(mixed_var) === '[object Array]') {
return false;
}
return mixed_var !== null && typeof mixed_var == 'object';
}
function merge(a, b) {
var cache = {};
cache = unpackObject(a, cache);
cache = unpackObject(b, cache);
return cache;
}
function unpackObject(a, cache) {
for (prop in a) {
if (a.hasOwnProperty(prop)) {
if (cache[prop] === undefined) {
cache[prop] = a[prop];
} else {
if (typeof cache[prop] === typeof a[prop]) {
if (is_object(a[prop])) {
cache[prop] = merge(cache[prop], a[prop]);
} else {
cache[prop] += a[prop];
}
}
}
}
}
return cache;
}
var a = {
en: 5,
fr: 3,
in : 9,
lang: "js",
object: {nestedProp: 6}
}
var b = {
en: 8,
fr: 21,
br: 8,
lang: "en",
object: {nestedProp: 1, unique: "myne"}
}
var c = merge(a, b);
fiddle here http://jsfiddle.net/vyFN8/1/
这是我的尝试，它是嵌套对象的递归 - https://gist.github.com/greenafrican/19bbed3d8baceb0a15fd
// Requires jQuery
// Merge nested objects and if the properties are numbers then add them together, else
// fallback to jQuery.extend() result
function mergeObjectsAdd(firstObject, secondObject) {
var result = $.extend(true, {}, firstObject, secondObject);
for (var k in result) {
if ("object" === typeof result[k]) {
firstObject[k] = firstObject[k] || {};
secondObject[k] = secondObject[k] || {};
result[k] = mergeObjectsAdd(firstObject[k], secondObject[k]);
} else {
firstObject[k] = firstObject[k] || 0;
secondObject[k] = secondObject[k] || 0;
result[k] = ("number" === typeof firstObject[k] && "number" === typeof secondObject[k]) ? (firstObject[k] + secondObject[k]) : result[k];
}
}
return result;
}
上一篇: 将C＃对象模板序列化为JSON