A guide on sorting an array of objects by their frequency within the array

My goal is to analyze an array of user objects, some of which are duplicated. The objective is to determine the frequency of each unique user object within the array and reorganize them so that the most frequently occurring user comes first while the least common user is placed at the end.

const users = 
[
   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a8c4c1dbc9e8cfc5c9c1c486cbc7c5">[email protected]</a>", createdAt: 1593894321997},
 
   {id: "bbfc927c-f3d4-4cdd-b872-9cb233a194aa", handle: "jisoo", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a7cdced4c8c8e7c0cac6cecb89c4c8ca">[email protected]</a>", createdAt: 1592452421714},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c6aca3a8a8afa386a1aba7afaae8a5a9ab">[email protected]</a>", createdAt: 1593894227232},

   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="7e12170d1f3e19131f1712501d1113">[email protected]</a>", createdAt: 1593894321997},

   {id: "1d1e31cd-eff2-47de-b46d-4d45bb2dd97f", handle: "kawikaLovesKpop", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2d464c5a44464c6d4a404c4441034e4240">[email protected]</a>", createdAt: 1593894550566},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="97fdf2f9f9fef2d7f0faf6fefbb9f4f8fa">[email protected]</a>", createdAt: 1593894227232},

   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="1c70756f7d5c7b717d7570327f7371">[email protected]</a>", createdAt: 1593894321997},

   {id: "1d1e31cd-eff2-47de-b46d-4d45bb2dd97f", handle: "kawikaLovesKpop", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="630802140a080223040e020a0f4d000c0e">[email protected]</a>", createdAt: 1593894550566},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8fe5eae1e1e6eacfe8e2eee6e3a1ece0e2">[email protected]</a>", createdAt: 1593894227232}
]

To achieve this, I attempted using the countBy method from lodash:

const bestMatched = countBy(users, "handle");

After running the code, the result showed:

{lisa: 3, jisoo: 1, unnieJennie: 3, kawikaLovesKpop: 2}

However, it is important for me to retain access to the original users array with all key-value pairs intact.

javascriptarrayssortingobject

Answer №1

To achieve this task, you can employ bitwise NOT. This is because ~undefined = -1, and an object is required to store the result:

const result = users.reduce((m,{handle})=>({...m, [handle]:-~m[handle]}), {})

Give it a try:

const users = 
[
   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a5c9ccd6c4e5c2c8c4ccc98bc6cac8">[email protected]</a>", createdAt: 1593894321997},
 
   {id: "bbfc927c-f3d4-4cdd-b872-9cb233a194aa", handle: "jisoo", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="cfa5a6bca0a08fa8a2aea6a3e1aca0a2">[email protected]</a>", createdAt: 1592452421714},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="08626d6666616d486f65696164266b6765">[email protected]</a>", createdAt: 1593894227232},

   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a6cacfd5c7e6c1cbc7cfca88c5c9cb">[email protected]</a>", createdAt: 1593894321997},

   {id: "1d1e31cd-eff2-47de-b46d-4d45bb2dd97f", handle: "kawikaLovesKpop", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d9b2b8aeb0b2b899beb4b8b0b5f7bab6b4">[email protected]</a>", createdAt: 1593894550566},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a5cfc0cbcbccc0e5c2c8c4ccc98bc6cac8">[email protected]</a>", createdAt: 1593894227232},

   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="dcb0b5afbd9cbbb1bdb5b0f2bfb3b1">[email protected]</a>", createdAt: 1593894321997},

   {id: "1d1e31cd-eff2-47de-b46d-4d45bb2dd97f", handle: "kawikaLovesKpop", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="91faf0e6f8faf0d1f6fcf0f8fdbff2fefc">[email protected]</a>", createdAt: 1593894550566},

   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="a3c9c6cdcdcac6e3c4cec2cacf8dc0ccce">[email protected]</a>", createdAt: 1593894227232}
]

const result = users.reduce((m,{handle})=>({...m, [handle]:-~m[handle]}), {})

console.log({result})

If you require ordered data, utilize an array since objects are not inherently ordered.

const result = users.reduce((m,{handle})=>({...m, [handle]:-~m[handle]}), {})
Object.keys(result).sort((a,b)=>result[a]-result[b]).map(key=>({[key]:result[key]}))

Answer №2

Give this a shot:

let counterObject = {}

for (userInfo of userInfos){
    counterObject[userInfo.username] = 1 + (counterObject[userInfo.username] || 0)
}

console.log(counterObject)

Answer №3

const userList = 
[
   {id: "0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8", handle: "lisa", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="fc90958f9dbc9b919d9590d29f9391">[email protected]</a>", createdAt: 1593894321997},
   {id: "bbfc927c-f3d4-4cdd-b872-9cb233a194aa", handle: "jisoo", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="761c1f05191936111b171f1a5815191b">[email protected]</a>", createdAt: 1592452421714},
   {id: "be942039-6a59-46a4-9f92-1f7808b20c2f", handle: "unnieJennie", email: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="49232c2727202c092e24282025672a2624">[email protected]</a>", createdAt: 1593894227232},
   // More user objects here...
]

let userCount = {lisa: 3, jisoo: 1, unnieJennie: 3, kawikaLovesKpop: 2}
userMap = new Map()
users.map(user => userMap.set(user.handle, user))
result = Object.entries(userCount).sort((a,b)=>b[1]-a[1])
.flatMap(obj =>Array(obj[1]).fill(userMap.get(obj[0])))

console.log(result)

Answer №4

It seems like the solution you were searching for has been found. Despite some initial JSON errors, everything appears to be in order now.

const users = [
  {
    id: '0f933bbd-d1fb-4ad5-80f0-661c3c0aa2f8',
    handle: 'lisa',
    email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="721e1b011332151f131b1e5c111d1f">[email protected]</a>',
    createdAt: 1593894321997,
  },
  // Remaining user objects...
];

function groupUsers(jsonArray) {
  var groupedArray = [];
  jsonArray.map((item, index) => {
    if (item !== 'null') {
      var newUserGroup = [];
      var itemHandle = item.handle;
      jsonArray.map((i, ind) => {
        if (itemHandle === i.handle && itemHandle !== 'null') {
          newUserGroup.push(i);
          jsonArray.splice(ind, 1, 'null');
        }
      });
      jsonArray.splice(index, 1, 'null');
      groupedArray.push(newUserGroup);
    }
  });
  return groupedArray;
}

var finalUserGroups = groupUsers(users);

// Sorting the finalUserGroups by frequency of occurrence
finalUserGroups.sort(function(a,b){
  return b.length - a.length
})

console.log(finalUserGroups)

This code ensures that related objects are kept together for easy access to their properties using dot notation.

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