How can I optimize the following JavaScript function

Question

I'm trying to optimize my code or see if there's a better way to do it. Given values for acctData and balances below, I need to return an array of accounts filtered by the user name. my code works

const acctData = [{
    acctNum: "AAA - 1234",
    user: "Alice"
  },
  {
    acctNum: "AAA - 5231",
    user: "Bob"
  },
  {
    acctNum: "AAA - 9921",
    user: "Alice"
  },
  {
    acctNum: "AAA - 8191",
    user: "Alice"
  }
];

const balance = {
  "AAA - 1234": 4593.22,
  "AAA - 9921": 0,
  "AAA - 5231": 232142.5,
  "AAA - 8191": 4344
};

const combinedAccBalance = JSON.parse(JSON.stringify(acctData));

const getAccountNumbers = (filterByUser) => {
  return combinedAccBalance
    .filter(acc => {
      acc.balance = balance[acc.acctNum];
      return acc.user === filterByUser;
    })
    .sort((a, b) => {
      return a.balance - b.balance;
    })
    .map(fa => {
      return fa.acctNum;
    });
};

console.log(getAccountNumbers("Alice"));
//Returns ["AAA - 9921", "AAA - 8191", "AAA - 1234"]

Consider posting this on Code Review since it works and you're asking for improvements. — VLAZ
– VLAZ, Commented Mar 19, 2020 at 6:15
This looks perfectly reasonable to me. But I don't think you need the deep copy action of const combinedAccBalance = JSON.parse(JSON.stringify(acctData)); as you are not changing anything in the array in getAccountNumbers(). The .filter() method will provide a shallow array copy, which is then sorted. So, no change to the original array. — Carsten Massmann
– Carsten Massmann, Commented Mar 19, 2020 at 6:23
Hi ! @cars10m I'm adding a new property acc.balance = balance[acc.acctNum]; where I'm filtering, so it does change the original array. Thoughts? — Patricio Vargas
– Patricio Vargas, Commented Mar 19, 2020 at 6:27

VLAZ · Accepted Answer · 2020-03-19 07:01:26Z

3

you can just skip the deep clone part and do something like this:

const acctData = [{
    acctNum: "AAA - 1234",
    user: "Alice"
  },
  {
    acctNum: "AAA - 5231",
    user: "Bob"
  },
  {
    acctNum: "AAA - 9921",
    user: "Alice"
  },
  {
    acctNum: "AAA - 8191",
    user: "Alice"
  }
];

const balance = {
  "AAA - 1234": 4593.22,
  "AAA - 9921": 0,
  "AAA - 5231": 232142.5,
  "AAA - 8191": 4344
};

let getAccountNumbers = (filterByUser) => {
  return acctData
    .filter(acc => acc.user === filterByUser)
    .sort((a, b) => {
      return balance[a.acctNum] - balance[b.acctNum];
    })
    .map(fa => {
      return fa.acctNum;
    });
};

console.log(getAccountNumbers("Alice"));
//Returns ["AAA - 9921", "AAA - 8191", "AAA - 1234"]

edited Mar 19, 2020 at 7:01

VLAZ

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answered Mar 19, 2020 at 6:52

aravind_reddy

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3 Comments

Patricio Vargas Over a year ago

ahhhhhh niceeee! Thanks!! I like that I don't have to make the copy of the array with this solution

aravind_reddy Over a year ago

yeah with this basically you could just avoid the whole copying thing and get the same result

Danny '365CSI' Engelman Over a year ago

removing the {} and return statements (like the filter), and doing the sort after the map will shorten it even more

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