将 Temp 替换为 Query

refactorgram

const basePrice = this._quantity * this._itemPrice;
if (basePrice > 1000)
  return basePrice * 0.95;
else
  return basePrice * 0.98;

get basePrice() {this._quantity * this._itemPrice;}

...

if (this.basePrice > 1000)
  return this.basePrice * 0.95;
else
  return this.basePrice * 0.98;