Iterate multiple arrays into object using javascript

Question

I have multiple arrays, the first one contains the keys, and the others contain the values.

Array[
  "name",
  "surname",
  "city",
  "age"
],
Array[
  "John",
  "Doe",
  "San Francisco",
  "27"
],
Array[
  "Nancy",
  "Doe",
  "New York",
  "15"
],
Array[
  "Maria",
  "Doe",
  "Texas",
  "30"
],

And I want to merge the arrays into an object like this:

{
  "name": "John"
  "surname": "Doe"
  "city": "San Francisco"
  "age": "27"
},
{
  "name": "Nancy"
  "surname": "Doe"
  "city": "New York"
  "age": "15"
},
{
  "name": "Maria"
  "surname": "Doe"
  "city": "Texas"
  "age": "30"
}

How can I do it using js as the length, keys and values of the arrays can change.

Hint: you may want to loop over Object.keys(...) of the first array — curiousdev
– curiousdev, Commented Mar 11, 2020 at 21:53
Do you have the arrays with the values in another array that you can loop over? — Barmar
– Barmar, Commented Mar 11, 2020 at 21:55
Your desired result is not an object, it's 3 different objects. Did you mean an array of objects? — Barmar
– Barmar, Commented Mar 11, 2020 at 21:56
@curiousdev Object.keys() is for objects, why would you use that on an array? — Barmar
– Barmar, Commented Mar 11, 2020 at 21:56

Nina Scholz · Accepted Answer · 2020-03-11 22:12:10Z

3

You could map over the values part and create new objects by iterating the first array as keys and take the actual value from the values part.

var data = [["name", "surname", "city", "age"], ["John", "Doe", "San Francisco", "27"], ["Nancy", "Doe", "New York", "15"], [ "Maria", "Doe", "Texas", "30"]],
    result = data
        .slice(1)
        .map(a => Object.fromEntries(data[0].map((k, i) => [k, a[i]])));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Mar 11, 2020 at 22:12

Nina Scholz

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1 Comment

Luiz Tokuhara Over a year ago

I just have added Object.fromEntries = data => Object.assign({}, ...Array.from(data, ([k, v]) => ({[k]: v}) )); as in nodejs Object.fromEntries is not supported.

Kim B · Accepted Answer · 2020-03-11 23:22:50Z

Your Array has semantic mistakes.

//This is your Array in JS:

let array = [
  ["name", "surname", "city", "age"],
  ["John", "Doe", "San Francisco", "27"],
  ["Nancy", "Doe", "New York", "15"],
  ["Maria", "Doe", "Texas", "30"]
];

//we need to sepparete keys and values
const keys = array.shift(); // ["name", "surname", "city", "age"]

//now array has just values and keys has the first item of an array

let arrOfObjects = array.map(item => {
  let obj = {};
  for (i = 0; i < item.length; i++) {
    obj[keys[i]] = item[i];
  }
  return obj;
});
console.log(arrOfObjects);

console:

[ { "name": "John", "surname": "Doe", "city": "San Francisco", "age": "27" }, { "name": "Nancy", "surname": "Doe", "city": "New York", "age": "15" }, { "name": "Maria", "surname": "Doe", "city": "Texas", "age": "30" } ]

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