Javasctipt better solution to add one property to array objects

December 21, 2021

Hello In javascript I have one array object

var arr=[{param: 'Invalid Entity Name', total: 2},
{param: 'Missing File', total: 1}];
console.log(arr);

My want is add one more attribute to objects. And this will be percentage. I can do it with two for loop as worst case but I want easier and smarter solution. as final result I want

var arr=[{param: 'Invalid Entity Name', total: 2,percent:67},
{param: 'Missing File', total: 1,percent:33}];
console.log(arr);

How can I make it?

Thanks in advance

>Solution :

In your case you have 2 things to do.

The first one is calculating the total and the second is for each element to calculate the percentage.

As you mention, you have to do 2 for loops indidually because each element have to know the total to calculate it’s percentage

This can be done with the reduce and forEach methods.

var arr=[
{param: 'Invalid Entity Name', total: 2},
{param: 'Missing File', total: 1}
];


const sumTotal = arr.reduce((total, current) => total + current.total, 0)

arr.forEach(element => {
  element.percent = Math.round(element.total / sumTotal * 100)
})

console.log(arr)