题解 | #数组过滤#

var cups = [
  { type: 1, price: 100, color: 'black', sales: 60, name: '牛客logo马克杯' },
  { type: 2, price: 40, color: 'blue', sales: 100, name: '无盖星空杯' },
  { type: 4, price: 60, color: 'green', sales: 200, name: '老式茶杯' },
  { type: 3, price: 50, color: 'green', sales: 600, name: '欧式印花杯' }
]
var select = document.querySelector('select');
var ul = document.querySelector('ul');

select.onchange = function () {
  let result;

  switch (+this.value) {
  case 1:
  result = cups.filter((item) => item.sales < 100)
  break
  case 2:
  result = cups.filter((item) => (item.sales <= 500 && item.sales >= 100))
  break
  case 3:
  result = cups.filter((item) => item.sales > 500)
  break
  }

  ul.innerHTML = result.reduce((lis, current) => lis += `<li>${current.name}</li>`, '')
}