Divide array to group indexes

I have a problem with the following logic in Javascript.

I have the following array, that have dynamic number of indexes, in this example I write one array with 2 indexes.

[[S,Blue],[M,Red],[L,Yellow]

I want to have this structure: { 0: [S,M,L], 1: [Blue,Red,Yellow] }

The numbers are the indexes of first group of array, what can I do?

I tried with for and map function but I don’t have the correct Logic

Answer

You can do this easily by first creating an object with Object.fromEntries(), then using Object.keys() and Object.values() to create an array.

function convertData(data) {
  const obj = Object.fromEntries(data);
  return [Object.keys(obj), Object.values(obj)];
}

const data = [['S', 'Blue'], ['M', 'Red'], ['L', 'Yellow']]
console.log(convertData(data))

Note: an object with numerical keys is the same as an array, therefore, you only need to create an array to fulfill the requirement.