How can someone loop a JSON and manipulate its values (convert to string, set fixed decimals and add thousands separator)?

Question

I fetch data from a third party API which returns 170 key:value items that represent currency exchange rates. Now I would like to loop that Object and manipulate the value items.

My idea is to

1. change the decimal number to 5
1. replace the existing "." with a "comma"
1. add thousand separators (".") to any value where the figure before the decimals is
  >= 1.000

Final output should look like e.g.

"BIF": 2088.228311 --> 2.088,22831.

The formula for the separator is from this thread which works pretty fine in a different project of mine: How to print a number with commas as thousands separators in JavaScript

Somehow my attempt shown below directly ends up in a SO error.

Any advice is highly appreciated :-) Thank you in advance!

let rates = {
        "AED": 4.07055,
  "AFN": 87.352472,
  "ALL": 123.333245,
  "AMD": 531.538368,
  "ANG": 1.931339,
  "AOA": 538.65376,
  "ARS": 66.131175,
  "AUD": 1.605893,
  "AWG": 1.994881,
  "AZN": 1.885024,
  "BAM": 1.95844,
  "BBD": 2.247575,
  "BDT": 94.335008,
  "BGN": 1.956646,
  "BHD": 0.417802,
  "BIF": 2088.228311,
  "BMD": 1.108267,
  "BND": 1.510167,
  "BOB": 7.697558,
  "BRL": 4.425866,
  "BSD": 1.113173,
  "BTC": 0.000118,
  "BTN": 78.682856,
  "BWP": 12.073536,
  "BYN": 2.272208,
  "BYR": 21722.032491,
}

Object.values(rates).forEach((value) => {
  .toFixed(5);
  .replace(/\B(?=(\d{3})+(?!\d))/g, ".");
  console.log(rates);
});

Don't get your idea yet. Could you provide a working example? — JSRB, Nov 06 '19 at 09:26

Mischa · Accepted Answer · 2019-11-06T09:36:59.100

Pleas note you cannot change the original rates-object in a forEach-loop (take a look here). Also better use standartized tools to format numbers instead of implementing your own workarounds (take a look here)

let rates = {
    "AED": 4.07055,
  "AFN": 87.352472,
  "ALL": 123.333245,
  "AMD": 531.538368,
  "ANG": 1.931339,
  "AOA": 538.65376,
  "ARS": 66.131175,
  "AUD": 1.605893,
  "AWG": 1.994881,
  "AZN": 1.885024,
  "BAM": 1.95844,
  "BBD": 2.247575,
  "BDT": 94.335008,
  "BGN": 1.956646,
  "BHD": 0.417802,
  "BIF": 2088.228311,
  "BMD": 1.108267,
  "BND": 1.510167,
  "BOB": 7.697558,
  "BRL": 4.425866,
  "BSD": 1.113173,
  "BTC": 0.000118,
  "BTN": 78.682856,
  "BWP": 12.073536,
  "BYN": 2.272208,
  "BYR": 21722.032491
}

for(key in rates) {
  rates[key] = new Intl.NumberFormat('de-DE', {
    minimumFractionDigits: 5,
    maximumFractionDigits: 5
  }).format(rates[key]);
   
}
console.log(rates);

How can someone loop a JSON and manipulate its values (convert to string, set fixed decimals and add thousands separator)?

1 Answers1