Filter the array of values from array of another value

Question

I am doing the filter declaring a final array. it seems that the codes are much. it can be shortened?

code :

const lookup = [
  {
    hfsUserCountryId: 2895,
    countryCd: 140,
  },
  {
    hfsUserCountryId: 2895,
    countryCd: 1301,
  },
];

const countries = [
  {
    "defaultOrder" : 0,
    "label" : "data.Code.Country_Cd.Code_Desc.US",
    "codeId" : 140,
    "code" : "US",
    "codeDesc" : "USA",
    "codeQualifier" : "Country_Cd"
  },
  {
    "defaultOrder" : null,
    "label" : "data.Code.Country_Cd.Code_Desc.AE",
    "codeId" : 1301,
    "code" : "AE",
    "codeDesc" : "United Arab Emirates",
    "codeQualifier" : "Country_Cd"
  },
  {
    "defaultOrder" : 1,
    "label" : "data.Code.Country_Cd.Code_Desc.AL",
    "codeId" : 1086,
    "code" : "AL",
    "codeDesc" : "Albania",
    "codeQualifier" : "Country_Cd"
  }, {
    "defaultOrder" : null,
    "label" : "data.Code.Country_Cd.Code_Desc.DZ",
    "codeId" : 2615,
    "code" : "DZ",
    "codeDesc" : "Algeria",
    "codeQualifier" : "Country_Cd"
  }
];

const final = []
const result = countries.filter(item =>{
  const {codeId} = item;
  const r = lookup.filter(look => {
    if( look.countryCd === codeId){
      final.push(item)
    }
  }  );
 
});

console.log('reuslt', final);

Live Demo

Answer 1

If you also want to improve performance. And that should only concern you if the lookup array is actually much larger than the one you provided. Consider converting the lookup array to a lookup map where keys would be the value of countryCd (or possibly create just a set of all countryCd values). Then you can do:

const codeIds = new Set(lookup.map((v) => v.countryCd))
const final = countries.filter((c) => codeIds.has(c.codeId))

Let m be the size of lookup array and n be the size of countries array. Time complexity of your original code, as well as @An Nguyen's, is O(n × m). My version is O(n + m).

Answer 2

I tried like this:

const c = countries.filter((county) => {
  return lookup.find(v => v.countryCd === county.codeId ?? county)
});

works. if any one have other thoughts please share.

Answer 3

Just need to use a filter function with array includes function.

const lookup = [
  {
    hfsUserCountryId: 2895,
    countryCd: 140,
  },
  {
    hfsUserCountryId: 2895,
    countryCd: 1301,
  },
];

const countries = [
  {
    "defaultOrder" : 0,
    "label" : "data.Code.Country_Cd.Code_Desc.US",
    "codeId" : 140,
    "code" : "US",
    "codeDesc" : "USA",
    "codeQualifier" : "Country_Cd"
  },
  {
    "defaultOrder" : null,
    "label" : "data.Code.Country_Cd.Code_Desc.AE",
    "codeId" : 1301,
    "code" : "AE",
    "codeDesc" : "United Arab Emirates",
    "codeQualifier" : "Country_Cd"
  },
  {
    "defaultOrder" : 1,
    "label" : "data.Code.Country_Cd.Code_Desc.AL",
    "codeId" : 1086,
    "code" : "AL",
    "codeDesc" : "Albania",
    "codeQualifier" : "Country_Cd"
  }, {
    "defaultOrder" : null,
    "label" : "data.Code.Country_Cd.Code_Desc.DZ",
    "codeId" : 2615,
    "code" : "DZ",
    "codeDesc" : "Algeria",
    "codeQualifier" : "Country_Cd"
  }
];

// const lookupIds = [1301, 140];
const lookupIds = lookup.map(({countryCd}) => countryCd);
const res = countries.filter(country => lookupIds.includes(country.codeId));
console.log('reuslt', res);