compare two objects array javascript code example

Example 1: javascript compare two arrays of objects get same elements

var result = result1.filter(function (o1) {
    return result2.some(function (o2) {
        return o1.id === o2.id; // return the ones with equal id
   });
});
// if you want to be more clever...
let result = result1.filter(o1 => result2.some(o2 => o1.id === o2.id));

Example 2: comparing array of objects in javascript

// IN THIS EXAMPLE WE HAVE GROUP INSERTS - DATA TO BE ADDED TO DB
// TO INSERT INTO DB EACH GROUP NAME MUST BE THE MATCHING ID
// CONATCT NAME MUST ALSO BE MATCHING ID
// THE CODE BELOW SHOWS HOW TO TRAVERSE THROGUH TWO ARRAYS AND COMPARE / ADD VALES

const groupInserts = [ { groups: [ 'Chess', 'Science', 'German' ], name: 'Ian Smith' },
  { groups: [ 'Swimming' ], name: 'Jenny Smith' },
  { groups: [ 'Tennis' ], name: 'Susan Jones' },
  { groups: [ 'Coding', 'Science' ], name: 'Judy Davis' } ]

const nameAndIdsFromDB = [ { name: 'Parent_1', id: 1 },
{ name: 'Parent_2', id: 2 },
{ name: 'Ian Smith', id: 99 },
{ name: 'Jenny Smith', id: 100 },
{ name: 'Susan Jones', id: 101 },
{ name: 'Judy Davis', id: 102 } ]

const groupnameAndIdsFromDB = [ { name: 'Debugging', id: 1 },
{ name: 'React', id: 2 },
{ name: 'New record with no people', id: 3 },
{ name: 'New record with people', id: 4 },
{ name: 'Chess', id: 12 },
{ name: 'Science', id: 13 },
{ name: 'German', id: 14 },
{ name: 'Swimming', id: 15 },
{ name: 'Tennis', id: 16 },
{ name: 'Coding', id: 17 } ]

let groupNamesWithIds = [];
groupInserts.forEach(data => {
    if (data.groups) {
         data.groups.map(e => {
                let obj = {};
                obj.group = e;
                obj.name = data.name
                groupNamesWithIds.push(obj);
        })
    }
})


let addedMessageGroupIds = [];
groupNamesWithIds.forEach(data => {
  groupnameAndIdsFromDB.map(e => {
    if (e.name === data.group) {
      addedMessageGroupIds.push({group: data.group, name: data.name, messages_individual_groups_id: e.id})
    }
  })
})

let addedContactIds = [];
addedMessageGroupIds.forEach(data => {
  nameAndIdsFromDB.map(e => {
    if (e.name === data.name) {
      addedContactIds.push({messages_individual_groups_id: data.messages_individual_groups_id, contact_id: e.id, created_at: Date.now()})
    }
  })
})