A simple array reducer example using objects

array_reducer_example_01.js

const array = [
  { id: 111, framework: 'react' },
  { id: 222, framework: 'angular' },
  { id: 333, framework: 'vue' }
];

const reducerCallback = (prevItem, currItem) => { 
  return { 
    id: prevItem.id + currItem.id, 
    framework: prevItem.framework + "-" + currItem.framework 
  }
}

console.log(array.reduce(reducerCallback)) // returns `{ id: 666, framework: 'react-angular-vue' }`