Group long object of dates, into object of months-CodePudding

I have a very long object of dates, which pairs a date with a price/number. For example:

let obj = {
"2022-09-17": 45,
"2022-09-18": 35,
"2022-09-19": 34,
"2022-09-20": 26,
"2022-09-21": 25,
"2022-09-22": 33,
"2022-09-23": 56,
"2022-09-24": 39,
"2022-09-25": 49,
"2022-09-26": 25,
"2022-09-27": 25,
"2022-09-28": 25,
"2022-09-29": 33,
"2022-09-30": 42,
"2022-10-01": 28,
"2022-10-02": 38,
"2022-10-03": 35,
"2022-10-04": 25,
"2022-10-05": 25,
"2022-10-06": 31
}

What is the best way to regroup this object as an array of months, which correlate to the dates and contain the key/values?

Eg - like this screenshot:

I want to group the key/value pair by months, so I can later, then loop through all months, to find the lowest price of each month.

But first, I wanted to figure out the best way to break up this object, in months?

Thanks,

CodePudding user response：

As often, reduce is a good solution here

let object = {
  "2022-09-17": 45,
  "2022-09-18": 35,
  "2022-09-19": 34,
  "2022-09-20": 26,
  "2022-09-21": 25,
  "2022-09-22": 33,
  "2022-09-23": 56,
  "2022-09-24": 39,
  "2022-09-25": 49,
  "2022-09-26": 25,
  "2022-09-27": 25,
  "2022-09-28": 25,
  "2022-09-29": 33,
  "2022-09-30": 42,
  "2022-10-01": 28,
  "2022-10-02": 38,
  "2022-10-03": 35,
  "2022-10-04": 25,
  "2022-10-05": 25,
  "2022-10-06": 31
}

const objectMonth = Object
  .keys(object)
  .reduce((acc, key) => {
    const date = new Date(key)
    const month = date.toLocaleString('default', { month: 'long' })
    acc[month] = acc[month] || []
    acc[month].push({
      date: key,
      price: object[key]
    })
    return acc
  }, {})

console.log(objectMonth)

CodePudding user response：

You can do something like this.

Logic

Loop through the entries in object
Split the date into year, month and date.
Get the month name with some logic.
Reduce this array of entries in the object.

let obj = {
  "2022-09-17": 45,
  "2022-09-18": 35,
  "2022-09-19": 34,
  "2022-09-20": 26,
  "2022-09-21": 25,
  "2022-09-22": 33,
  "2022-09-23": 56,
  "2022-09-24": 39,
  "2022-09-25": 49,
  "2022-09-26": 25,
  "2022-09-27": 25,
  "2022-09-28": 25,
  "2022-09-29": 33,
  "2022-09-30": 42,
  "2022-10-01": 28,
  "2022-10-02": 38,
  "2022-10-03": 35,
  "2022-10-04": 25,
  "2022-10-05": 25,
  "2022-10-06": 31,
};
const months = [
  "january",
  "february",
  "march",
  "april",
  "may",
  "june",
  "july",
  "august",
  "september",
  "october",
  "november",
  "december",
];
const splittedData = Object.entries(obj).reduce(
  (acc, [dateStr, value]) => {
    const [year, month, date] = dateStr.split("-");
    if (!acc[months[ month - 1]]) {
      acc[months[ month - 1]] = [];
    }
    acc[months[ month - 1]].push({ [dateStr]: value });
    return acc;
  },
  []
);
console.log(splittedData);