Compare 2 objects and update the matching object in javascript

July 5, 2022

I want to compare 2 array of objects and update the matching object as well as total count in the object

let arr1 = [{status: 'Total', count: 0, text: 'Total applications'},
{status: 'submitted', count: 0, text: 'Applications submitted'},
{status: 'Rejected', count: 0, text: 'Applications rejected'}]

let arr2 = [
   {status: "submitted", count: 20} ,
{status: "Rejected", count: 10}
]

function

 let finalResult = arr2.map(function(a){
       var result=arr1.filter(b=> a.status==b.status ?  {...a, count:b.count} : arr1[0].count:arr1[0].count  );
       return result
     
   })

Final Result should be like this:

 [{status: 'Total', count: 30, text: 'Total applications'},
{status: 'submitted', count: 20, text: 'Applications submitted'},
{status: 'Rejected', count:10, text: 'Applications rejected'}
]

>Solution :

You can simply loop through second array and build a hash map and also find total value. now just loop over first array and update values accordingly

let arr1 = [{status: 'Total', count: 0, text: 'Total applications'},{status: 'submitted', count: 0, text: 'Applications submitted'},{status: 'Rejected', count: 0, text: 'Applications rejected'}]

let arr2 = [{status: "submitted", count: 20} ,{status: "Rejected", count: 10}]

let total = 0;
let obj = {}

// finding total and build hash map
arr2.forEach(data => {
  obj[data.status] = obj[data.status] || data
  total += data.count
})

// loop over first array and update count accordingly
let final = arr1.map(data => {
  if(data.status === 'Total'){
    return {...data, count: total}
  } else if(data.status in obj){
    return {...data, ...obj[data.status]}
  } else {
    return data
  }
})

console.log(final)