Javascript 将 object 插入到这样的数组中 [{…}, {…}]

Question

Suppose I have a variable called var testVar = [];And I have a data in ajax like this

{
  "Country": "ALA Aland Islands",
  "CountryCode": "AX",
  "Slug": "ala-aland-islands",
  "Population": 100000,
  "Teenagers": 50000,
  "Mid": 20000,
  "Seniors": 30000
},
{
  "Country": "Afghanistan",
  "CountryCode": "AFR",
  "Slug": "afghanistan",
  "Population": 200000,
  "Teenagers": 50000,
  "Mid": 100000,
  "Seniors": 50000
}

I'm trying to do a for loop and insert the population per country in the array (testVar) by doing it like this

function obj(key, val) {
this.key = key;
this.val = val;
}
for(i=0;i<data.lenght;i++){
    var x = new obj("y",data[i].Population);
    testVar.push(x); 
}

although the above works, it still didn't achieve what I'm trying to do. what i want the data to look like should be something like this

[{...}], [{...}] instead of [obj,obj]

Answer 1

It's a fairly simple solution

All we do is map the ajax response to only the population key.

 let data = [{ "Country": "ALA Aland Islands", "CountryCode": "AX", "Slug": "ala-aland-islands", "Population": 100000, "Teenagers": 50000, "Mid": 20000, "Seniors": 30000 }, { "Country": "Afghanistan", "CountryCode": "AFR", "Slug": "afghanistan", "Population": 200000, "Teenagers": 50000, "Mid": 100000, "Seniors": 50000 } ]; console.log('Standard Approach'); console.log(data.map((location) => ({ Population: location.Population }))) console.log('Property Destructuring'); console.log(data.map(({Population}) => ({ Population }))) console.log('Using Y && Standard Approach'); console.log(data.map((location) => ({ y: location.Population }))) console.log('Using Y && Property Destructuring'); console.log(data.map(({Population}) => ({ y: Population })))