JSFiddle - React, Tailwind, and code Playground

JavaScript

var arraySource = [];
arraySource.push({key : "fr", value: "france"});
arraySource.push({key : "es", value: "spain"});
//...

console.debug(arraySource);

var destJson = {};

$.each(arraySource, function (index, item) {
    destJson[item.key] = item.value;
});

console.debug(destJson);