Filter array of objects by object property

Question

I got array of objects

const countryList =  [
    { name: 'Afghanistan', id: 'AF' },
    { name: 'Åland Islands', id: 'AX' },
    { name: 'Albania', id: 'AL' },
    { name: 'Algeria', id: 'DZ' }]

I want to filter the array by object "id" and get name

Here is what I have already done and it is working

getName = (id) => {
    let name=[]
    for (var i = 0; i < countryList.length ; i++) {
        if (countryList[i].id === id) {
            name.push(countryList[i]);                
        } 
    }
    console.log(name[0].name)
}

Is there any better way of doing it?

Nina Scholz · Accepted Answer · 2019-05-11 17:44:11Z

1

You could find the name, if id is unique and take for unknow items a default object.

const
    getName = id => (countryList.find(o => o.id === id) || {}).name,
    countryList = [{ name: 'Afghanistan', id: 'AF' }, { name: 'Åland Islands', id: 'AX' }, { name: 'Albania', id: 'AL' }, { name: 'Algeria', id: 'DZ' }];

console.log(getName('AL'));
console.log(getName('UK'));

answered May 11, 2019 at 17:44

Nina Scholz

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Comments

Christos · Accepted Answer · 2019-05-11 17:49:27Z

0

You could make use of find array method:

const countryList =  [
    { name: 'Afghanistan', id: 'AF' },
    { name: 'Åland Islands', id: 'AX' },
    { name: 'Albania', id: 'AL' },
    { name: 'Algeria', id: 'DZ' }];
    
    
getName = (id) => {
  let country = countryList.find(c=>c.id === id);
  return country !== undefined
     ? country.name
     : 'not found';
}

console.log(getName('DZ'));

Note here that the getName returns now a string and doesn't have any side effects like logging the found value in the console. Also the function now does exactly what it's name says, just gets the name.

For further info regrading this method, please have a look here.

edited May 11, 2019 at 17:49

answered May 11, 2019 at 17:46

Christos

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2 Comments

Maheer Ali Over a year ago

Just simply checking country will be fine in this case because undefined is a falsy value. return country ? country.name : 'not found';

Christos Over a year ago

@MaheerAli You are correct. However for someone that doesn't know what the find returns in case of not an element is found, it is more clear to state that returns undefined rather than null for example.

Aaron Dov Malkin · Accepted Answer · 2019-05-11 17:46:14Z

0

You don't need the "name" array.

getName = (id) => {
    for (var i = 0; i < countryList.length ; i++) {
        if (countryList[i].id === id) {
            console.log(name[i].name);
        } 
    }
}

answered May 11, 2019 at 17:46

Aaron Dov Malkin

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Comments

Maheer Ali · Accepted Answer · 2019-05-11 17:52:32Z

0

You can use find() to get the object and then return the name of that object.

const countryList = [ { name: 'Afghanistan', id: 'AF' }, { name: 'Åland Islands', id: 'AX' }, { name: 'Albania', id: 'AL' }, { name: 'Algeria', id: 'DZ' } ]
const getName = id => (countryList.find(x => x.id === id) || {}).name

console.log(getName('AX'))
console.log(getName('DZ'))

edited May 11, 2019 at 17:52

answered May 11, 2019 at 17:42

Maheer Ali

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1 Comment

delmin Over a year ago

that is what I was looking for. Thanks both of you and hopefully I can mark both answers as correct (in 6 minutes). Unfortunately I can not upvote your answers due to my low points. What a nerdy ridiculous rules :D

Meshack Mbuvi · Accepted Answer · 2019-05-11 18:01:20Z

0

I think this works too

const countryList =  [
{ name: 'Afghanistan', id: 'AF' },
{ name: 'Åland Islands', id: 'AX' },
{ name: 'Albania', id: 'AL' },
{ name: 'Algeria', id: 'DZ' }];

getName=(id)=>{
    countryList.filter(item=>{item.id===id})
    console.log(countryList[0].name)
}

answered May 11, 2019 at 18:01

Meshack Mbuvi

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Comments

ontananza · Accepted Answer · 2019-05-11 18:03:59Z

0

You could do with array.some for performance reasons, if country id is unique.

getCountryName = (countryList, id) => {
    name = null;
    countryList.some((x, idx) => {
        result = false;
        if(x.id === id) {
            name = x.name;
            result = true;
        }
        return result;
    });
    return name;
}

Usage is

getCountryName(countryList, 'AF')

Result is

'Afghanistan'

answered May 11, 2019 at 18:03

ontananza

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