如何在javascript中通过id从对象数组中获取唯一数据

Question

您好，我需要帮助，我正在尝试从一个对象的数组中通过id在JavaScript中获取唯一的数据，我不能获取它下面是我的数组

[
  {id: 408, customer_id: 2, bill_no: 381, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 409, customer_id: 3, bill_no: 382, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 410, customer_id: 4, bill_no: 383, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 411, customer_id: 6, bill_no: 384, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 412, customer_id: 7, bill_no: 385, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 413, customer_id: 8, bill_no: 386, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 414, customer_id: 9, bill_no: 387, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 387, customer_id: 2, bill_no: 360, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 388, customer_id: 3, bill_no: 361, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 389, customer_id: 4, bill_no: 362, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 390, customer_id: 6, bill_no: 363, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 391, customer_id: 7, bill_no: 364, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 392, customer_id: 8, bill_no: 365, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 393, customer_id: 9, bill_no: 366, bill_period: 'weekly', from_date: '2021-10-03'}
  {id: 380, customer_id: 2, bill_no: 353, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 381, customer_id: 3, bill_no: 354, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 382, customer_id: 4, bill_no: 355, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 383, customer_id: 6, bill_no: 356, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 384, customer_id: 7, bill_no: 357, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 385, customer_id: 8, bill_no: 358, bill_period: 'weekly', from_date: '2021-09-26'}
  {id: 386, customer_id: 9, bill_no: 359, bill_period: 'weekly', from_date: '2021-09-26'}
]

我想要customer_id从上面的数组中得到唯一的数据和它们的最新id，我想要像下面的代码一样的结果

[
  {id: 408, customer_id: 2, bill_no: 381, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 409, customer_id: 3, bill_no: 382, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 410, customer_id: 4, bill_no: 383, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 411, customer_id: 6, bill_no: 384, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 412, customer_id: 7, bill_no: 385, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 413, customer_id: 8, bill_no: 386, bill_period: 'weekly', from_date: '2021-10-10'}
  {id: 414, customer_id: 9, bill_no: 387, bill_period: 'weekly', from_date: '2021-10-10'}
]

Answer 1

没有现成的函数，你需要自己编写；但它应该很简单。减速机的一个很好的用例！

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

​

const arr = [
  {id: 408, customer_id: 2, bill_no: 381, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 409, customer_id: 3, bill_no: 382, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 410, customer_id: 4, bill_no: 383, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 411, customer_id: 6, bill_no: 384, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 412, customer_id: 7, bill_no: 385, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 413, customer_id: 8, bill_no: 386, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 414, customer_id: 9, bill_no: 387, bill_period: 'weekly', from_date: '2021-10-10'},
  {id: 387, customer_id: 2, bill_no: 360, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 388, customer_id: 3, bill_no: 361, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 389, customer_id: 4, bill_no: 362, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 390, customer_id: 6, bill_no: 363, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 391, customer_id: 7, bill_no: 364, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 392, customer_id: 8, bill_no: 365, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 393, customer_id: 9, bill_no: 366, bill_period: 'weekly', from_date: '2021-10-03'},
  {id: 380, customer_id: 2, bill_no: 353, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 381, customer_id: 3, bill_no: 354, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 382, customer_id: 4, bill_no: 355, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 383, customer_id: 6, bill_no: 356, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 384, customer_id: 7, bill_no: 357, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 385, customer_id: 8, bill_no: 358, bill_period: 'weekly', from_date: '2021-09-26'},
  {id: 386, customer_id: 9, bill_no: 359, bill_period: 'weekly', from_date: '2021-09-26'}
];

// reduce array to only relevant values to a single variable
const filtered = arr.reduce((accumulator, current) => {
  // If customer data is already added to accumulator, don't add
  if (accumulator.find(x => x.customer_id ===  current.customer_id)) {
    return accumulator;
  }

  accumulator.push(current);
  return accumulator;
}, []);

console.log(filtered);

​