以YYYY-MM-DD格式从一个数组中获取上个月的所有记录

function getRecordsLastMonth(records) {
  var currentDate = new Date();
  var lastMonthYear = currentDate.getFullYear();
  var lastMonthMonth = currentDate.getMonth() - 1;

  // 处理跨年的情况
  if (lastMonthMonth < 0) {
    lastMonthYear -= 1;
    lastMonthMonth = 11; // 12月的索引为11
  }

  var lastMonthRecords = [];

  for (var i = 0; i < records.length; i++) {
    var recordDate = new Date(records[i].date);

    if (
      recordDate.getFullYear() === lastMonthYear &&
      recordDate.getMonth() === lastMonthMonth
    ) {
      lastMonthRecords.push(records[i]);
    }
  }

  var formattedLastMonthRecords = lastMonthRecords.map(function (record) {
    var date = new Date(record.date);
    var formattedDate =
      date.getFullYear() +
      '-' +
      ('0' + (date.getMonth() + 1)).slice(-2) +
      '-' +
      ('0' + date.getDate()).slice(-2);
    return {
      ...record,
      date: formattedDate,
    };
  });

  return formattedLastMonthRecords;
}

// 示例数据
var records = [
  { date: '2022-05-01', value: 100 },
  { date: '2022-04-15', value: 200 },
  { date: '2022-04-30', value: 150 },
  { date: '2022-03-20', value: 300 },
];

var lastMonthRecords = getRecordsLastMonth(records);
console.log(lastMonthRecords);