如何使用问题运算符优化代码

Question

我的代码中有多个条件！所以我正在考虑使用问题操作符而不是if() .. else..。但是我不太理解这个运算符。

这是我的代码：

if(this.intake.repairdamageInfo.additionalinfo){
  damageObjectModel.price = this.intake.repairdamageInfo.additionalinfo.newPrice;
  damageObjectModel.store = this.intake.repairdamageInfo.additionalinfo.storePurchase;
  damageObjectModel.dayValue = this.intake.repairdamageInfo.additionalinfo.dayValue;
}
else {
  damageObjectModel.price = "";
  damageObjectModel.store = "";
  damageObjectModel.dayValue = "";
} 

我试着这样做，但没有效果：

  damageObjectModel.price = this.intake.repairdamageInfo.additionalinfo?.newPrice;
  damageObjectModel.store = this.intake.repairdamageInfo.additionalinfo?.storePurchase;
  damageObjectModel.dayValue = this.intake.repairdamageInfo.additionalinfo?.dayValue;

有人能帮我吗？

Answer 1

我会解构并将空字符串指定为默认值：

const { newPrice = '', storePurchase = '', dayValue = '' } = this.intake.repairdamageInfo.additionalinfo ?? {};
Object.assign(damageObjectModel, { price: newPrice, store: storePurchase, dayValue });

如果additionalInfo为空，则?? {}将意味着整个右侧将计算为空对象。

你的原始代码

damageObjectModel.price = this.intake.repairdamageInfo.additionalinfo?.newPrice;

不起作用，因为如果链失败，?.可选链接将计算为undefined，而不是空字符串。