Best practices for extracting values from an array in JavaScript

I am looking to extract specific values from a MAP in JavaScript based on its id ("codi" within the object).

My array resembles the following but is larger:

0: {codi: '291', literal: 'MEDIFIATC Progres 2010 ', check: true}
1: {codi: '292', literal: 'MEDIFIATC Progres < 2010 ', check: true}
2: {codi: '293', literal: 'MEDIFIATC Progres ', check: true}
3: {codi: '294', literal: 'MEDIFIATC Progres 2013 ', check: true}
4: {codi: '295', literal: 'MEDIFIATC Progres 2014 ', check: true}
5: {codi: '296', literal: 'MEDIFIATC MEDIFIATC ', check: true}
6: {codi: '297', literal: 'MEDIFIATC MEDIFIATC P5 ', check: true}
7: {codi: '298', literal: 'MEDIFIATC MEDIFIATC P15 ', check: true}
8: {codi: '299', literal: 'MEDIFIATC MEDIFIATC DIAGONAL ', check: true}

Currently, I am using a simple loop where I iterate through and return the entry when my variable matches the "codi".

function getSubgroup(codi) {
    for(j = 0; j < Object.keys(subGroupList).length; j++) {
        if (codi == subGroupList[i].codi) {
            return subGroupList[i];
        }
    }   
}

How can I enhance this process?

In addition, I need to extract the values that I will be returning from my primary array. Currently using information from: How can I remove a specific item from an array? , any further assistance on this would be appreciated.

Thank you.

EDIT: I would like to share useful links here provided by Simone Rossaini in the comments:

javascriptarraysjsonperformanceloops

Answer №1

It would be most efficient to invest in transforming the object into a map with the key as the codi and the value as the actual object. This way, any further extraction can be done in constant time O(1).

var obj = {
  0: {codi: '291', literal: 'MEDIFIATC Progres 2010 ', check: true},
  1: {codi: '292', literal: 'MEDIFIATC Progres < 2010 ', check: true},
  2: {codi: '293', literal: 'MEDIFIATC Progres ', check: true},
  3: {codi: '294', literal: 'MEDIFIATC Progres 2013  ', check: true},
  4: {codi: '295', literal: 'MEDIFIATC Progres 2014 ', check: true},
  5: {codi: '296', literal: 'MEDIFIATC MEDIFIATC  ', check: true},
  6: {codi: '297', literal: 'MEDIFIATC MEDIFIATC P5 ', check: true},
  7: {codi: '298', literal: 'MEDIFIATC MEDIFIATC P15 ', check: true},
  8: {codi: '299', literal: 'MEDIFIATC MEDIFIATC DIAGONAL ', check: true}
}

// converting the object into an array
// disregard if already an array
var arr = Object.values(obj)

var result = arr.reduce(function(agg,item) {
  agg[item.codi] = item;
  return agg;
}, {})

console.log(result);
// now you can:
console.log(result["294"]);

Answer №2

If you're aiming for the best performance, conducting benchmarks is essential. However, keep in mind that optimal results may vary between different browsers and runtime environments.

Consider utilizing newer array methods in JavaScript such as find. It's worth noting that filter might be slower since it continues iterating even after finding a match, searching for additional matches.

item = listOfItems.find(item => item.code === targetCode)

Answer №3

When the unique values of codi are considered, you can transform the array into either a Map or an object using the codi value as the key. This approach simplifies accessing the data.

An older question with various answers discussing the merits of each structure will aid in determining which one to utilize.

Map:

const arr=[{codi:"291",literal:"MEDIFIATC Progres 2010 ",check:!0},{codi:"292",literal:"MEDIFIATC Progres < 2010 ",check:!0},{codi:"293",literal:"MEDIFIATC Progres ",check:!0},{codi:"294",literal:"MEDIFIATC Progres 2013  ",check:!0},{codi:"295",literal:"MEDIFIATC Progres 2014 ",check:!0},{codi:"296",literal:"MEDIFIATC MEDIFIATC  ",check:!0},{codi:"297",literal:"MEDIFIATC MEDIFIATC P5 ",check:!0},{codi:"298",literal:"MEDIFIATC MEDIFIATC P15 ",check:!0},{codi:"299",literal:"MEDIFIATC MEDIFIATC DIAGONAL ",check:!0}];

const map = new Map();

for (const obj of arr) {
  map.set(obj.codi, obj);
}

console.log(map.get('298'));

Object:

const arr=[{codi:"291",literal:"MEDIFIATC Progres 2010 ",check:!0},{codi:"292",literal:"MEDIFIATC Progres < 2010 ",check:!0},{codi:"293",literal:"MEDIFIATC Progres ",check:!0},{codi:"294",literal:"MEDIFIATC Progres 2013  ",check:!0},{codi:"295",literal:"MEDIFIATC Progres 2014 ",check:!0},{codi:"296",literal:"MEDIFIATC MEDIFIATC  ",check:!0},{codi:"297",literal:"MEDIFIATC MEDIFIATC P5 ",check:!0},{codi:"298",literal:"MEDIFIATC MEDIFIATC P15 ",check:!0},{codi:"299",literal:"MEDIFIATC MEDIFIATC DIAGONAL ",check:!0}];

const out = {};

for (const obj of arr) {
  out[obj.codi] = obj;
}

console.log(out['298']);

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