如何使用lodash合并两个数组并对重复对象的值求和

Question

有两个数组：

[
  {"id": "5c5030b9a1ccb11fe8c321f4", "quantity": 1},
  {"id": "344430b94t4t34rwefewfdff", "quantity": 5},
  {"id": "342343343t4t34rwefewfd53", "quantity": 3}
]

和

[
  {"id": "5c5030b9a1ccb11fe8c321f4", "quantity": 2},
  {"id": "344430b94t4t34rwefewfdff", "quantity": 1}
]

如何将它们合并为一个求和量？

[
  {"id": "5c5030b9a1ccb11fe8c321f4", "quantity": 3},
  {"id": "344430b94t4t34rwefewfdff", "quantity": 6},
  {"id": "342343343t4t34rwefewfd53", "quantity": 3}
]

其中之一有时可能是空的

Answer 1

您可以使用纯 JavaScript 来实现。

用于Array.reduce()通过 id 制作一个中间字典并累积数量，然后将其转换为一个数组Object.values()：

const arr1 = [
  {"id": "5c5030b9a1ccb11fe8c321f4", "quantity": 1},
  {"id": "344430b94t4t34rwefewfdff", "quantity": 5},
  {"id": "342343343t4t34rwefewfd53", "quantity": 3}
];
const arr2 = [
  {"id": "5c5030b9a1ccb11fe8c321f4", "quantity": 2},
  {"id": "344430b94t4t34rwefewfdff", "quantity": 1}
];

const result = Object.values([...arr1, ...arr2].reduce((acc, { id, quantity }) => {
  acc[id] = { id, quantity: (acc[id] ? acc[id].quantity : 0) + quantity  };
  return acc;
}, {}));

console.log(result);