Combining two objects in JavaScript?

Question

I have two JSON files.

one looks like this:

    {
base: "EUR",
date: "2019-01-30",

rates: {

    USD: 1.1429,
    AND MORE....
    ...
    ...

}
}

and another one that looks like this:

{
results: {
USD: {
    currencyName: "United States Dollar",
    currencySymbol: "$",
    id: "USD"
}
}

I want to combine them together and get an object that looks like this:

{
results: {
USD: {
    currencyName: "United States Dollar",
    currencySymbol: "$",
    id: "USD",
    value: 1.1429   <====== the change
}
}

I couldn't find anything similar here... and have no idea how to begin

I am getting the values from these links:

https://free.currencyconverterapi.com/api/v6/currencies

https://api.exchangeratesapi.io/latest

with fetch function:

function getdataFromApiAsync() {
  return fetch('https://api.exchangeratesapi.io/latest')
    .then((response) => response.json())
    .then((responseJson) => {
      return responseJson.rates;
    })
    .catch((error) => {
      console.error(error);
    });
}

so you have to loop over the one and add it to the other.... going to be loops.... — epascarello, Jan 30 '19 at 17:12
What you posted as "JSON" is not JSON at all. [There's no such thing as a "JSON Object"](http://benalman.com/news/2010/03/theres-no-such-thing-as-a-json/) — Randy Casburn, Jan 30 '19 at 17:13
@RandyCasburn read the question and the code. there's a ".json()" function. — Dor Lugasi-Gal, Jan 30 '19 at 17:17
This: _I have two JSON files. one looks like this:_ :: Neither of the code blocks that follow contain JSON. — Randy Casburn, Jan 30 '19 at 17:18
@RandyCasburn this is really not the point. instead of discussing the semantic. you can try to help with a function :) — Dor Lugasi-Gal, Jan 30 '19 at 17:19
As epascarello points out - loop over one and add it to the other. Best of luck to you. — Randy Casburn, Jan 30 '19 at 17:21
https://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically — Fahad Abid, Jan 30 '19 at 17:22
https://jsfiddle.net/ydp5n9fx/ do you want something like this? — Sarmad Shah, Jan 30 '19 at 17:22
Do tell me if you want something like this, or if you want to loop over results, if the results is array — Sarmad Shah, Jan 30 '19 at 17:23
Might want to look at using the spread operator if you have it available. — Bardicer, Jan 30 '19 at 17:26

score 1 · Accepted Answer · answered Jan 30 '19 at 17:32

Assuming that your results object has an interface sort of like this:

{
  [key: string]: {
    currencyName: string;
    currencySymbol: string;
    id: string;
    value?: number;
  }
}

where the id here always matches to a key of the rates object, then you would probably want to loop through the values of this results object and add a value from the other object's rates, like this:

Object.values(results).forEach(result => {
  const value = rates[result.id];
  if (value) {
    result.value = value;
  }
});

Combining two objects in JavaScript?

1 Answers1