题解 | JS21 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');
        // 补全代码
        select.onchange = function(e){
            const value = this..value;
            let filterCups;
            switch(value){
                case '1': 
                    filterCups = cups.filter(item=>item.sales < 100)
                    break;
                case '2':
                    filterCups = cups.filter(item=>(item.sales <= 500) && (item.sales >= 100))
                    break;
                case '3':
                    filterCups = cups.filter(item=>item.sales > 500)
                default:
                    break;
            }
            let str = '';
            filterCups.forEach(cup=>{
                str += '<li>' + cup.name + '</li>'
            })
            ul.innerHTML = str;
        }