将具有某些新属性的对象数组添加到另一个同名的对象数组中

let existingArray = [
  { id: 1, name: 'Alice' },
  { id: 2, name: 'Bob' }
];

let newArray = [
  { id: 3, name: 'Charlie' },
  { id: 4, name: 'David' }
];

existingArray.push(...newArray);
console.log(existingArray);

const _ = require('lodash');

let existingArray = [
  { id: 1, name: 'Alice', details: { age: 25 } },
  { id: 2, name: 'Bob', details: { age: 30 } }
];

let newArray = [
  { id: 1, name: 'Alice', details: { age: 26 } },
  { id: 3, name: 'Charlie', details: { age: 35 } }
];

let mergedArray = _.unionBy(existingArray, newArray, 'id');
console.log(mergedArray);

function mergeObjects(obj1, obj2) {
  return { ...obj1, ...obj2 };
}

let mergedArray = existingArray.map(item => 
  newArray.find(newItem => newItem.id === item.id) || item
).map(item => mergeObjects(item, newArray.find(newItem => newItem.id === item.id)));