How do I sort dates in JSON in the format MMM DD, YYYY?

Question

I have a JSON file which contains the following data:

{
  "Aug 24, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",

  ],
  "Aug 23, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ],
  "Aug 22, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ]
}

I want to sort the key (dates) before using the JSON data in my code. Is it possible to sort date in this format in Javascript?

https://stackoverflow.com/questions/4222690/sorting-a-json-object-in-javascript — zvi, Aug 25 '20 at 20:24
Don't expect properties of an object to be sorted. Although there is some logic behind how they are ordered, the best practice is to us an *array* when order is important, not a plain object. — trincot, Aug 25 '20 at 20:25
Are you really working with JSON here, or is this a JavaScript object (that doesn't need JSON parsing)? — trincot, Aug 25 '20 at 20:29
Since ES6 keys are guaranteed to be in order of insertion. In ES5 they were not guaranteed by the standard to be in order. — Adrian Brand, Aug 25 '20 at 20:43

score 0 · Accepted Answer · answered Aug 25 '20 at 20:27

You can sort the properties by key as Date objects:

let dates = {
  "Aug 24, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",

  ],
  "Aug 23, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ],
  "Aug 22, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ]
}
dates = Object.keys(dates)
          .sort((a,b) => new Date(a) - new Date(b))
          .reduce(function (result, key) {
               result[key] = dates[key];
               return result;
          }, {});

console.log(dates);

Adrian Brand · Answer 2 · 2020-08-25T20:37:08.873

const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

const parseDate = str => new Date(
  parseInt(str.substr(8, 4)),
  months.indexOf(str.substr(0, 3)),
  parseInt(str.substr(4, 2))
);

const values = {
  "Aug 24, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",

  ],
  "Aug 23, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ],
  "Aug 22, 2020": [
    "weather alert.",
    "new message",
    "you have a new request.",
  ]
};

const sortKeysByDate = obj => Object.keys(obj)
  .sort((a, b) => parseDate(a).getDate() - parseDate(b).getDate())
  .reduce((result, key) => {
    result[key] = obj[key];
    return result;
  }, {});

console.log(sortKeysByDate(values));

How do I sort dates in JSON in the format MMM DD, YYYY?

2 Answers2