how to group an array of objects
const groupBy = (array, key) => {
// Return the end result
return array.reduce((result, currentValue) => {
// If an array already present for key, push it to the array. Else create an array and push the object
(result[currentValue[key]] = result[currentValue[key]] || []).push(
currentValue
);
// Return the current iteration `result` value, this will be taken as next iteration `result` value and accumulate
return result;
}, {}); // empty object is the initial value for result object
};