JSFiddle - React, Tailwind, and code Playground

by Dmitry Luzanov

JavaScript

const target = [{id: 1}, {id: 2}, {id: 1}, {id: 3}]

const getCountIds = target => {
	const result = new Object
  
  target.forEach(item => result[item.id] ? result[item.id]++ : result[item.id] = 1)
  
  return Object.keys(result).map(item => {
  	return {
    	id: parseInt(item),
      sum: result[item]
    }
  })
}

console.log(getCountIds(target))