Javascript：按键合并对象

Question

I have an array of objects that looks like this:

var countries = [
    {id: SWE, value: 5},
    {id: DE, value:10},
    {id: SWE, anotherValue: 11},
    {id: DE, anotherValue: 15}
]

I want to merge array elements by id. The result should look like this:

countries = [
    {id: SWE, value: 5, anotherValue: 11},
    {id: DE, value:10, anotherValue:15}
]

Right now, I'm doing this with a for loop and a lot of if and else .

Question: is there any (more elegant) javascript inbuilt functionality to achieve this?

I've tried googling this, the problem is that I'm not sure what to Google for (I'm a javascript newby). Any help is appreciated.

Answer 1

try this:

 function mergeById(a){ var obj={}; a.forEach(function(e){ if(e && e.id){ obj[e.id] = obj[e.id] || {}; for(var _k in e) obj[e.id][_k] = e[_k] } }); return Object.keys(obj).map(function (key) {return obj[key]}); } var countries = [ {id: 'SWE', value: 5}, {id: 'DE', value:10}, {id: 'SWE', anotherValue: 11}, {id: 'DE', anotherValue: 15} ] document.write(JSON.stringify(mergeById(countries)))