Question

我在const city未处理拒绝（TypeError）中遇到错误：无法读取未定义的属性'value'

handleClick = async(e) => {
    e.preventDefault();
    const city = e.target.elements.city.value;
    const api=await fetch(`http://api.openweathermap.org/data/2.5/weather?q=${city}&units=metric&appid=563f12881628bc03a04f230c259dd4f9`);
    const rtr = await api.json();
   this.setState({
     temperature:rtr.main.temp,
     humidity:rtr.main.humidity,
     city:rtr.name,
     country:rtr.sys.country
   });
  }

期望通过api调用来获取城市

Answer 1

您应该添加if语句以检查城市是否存在。

handleClick = async(e) => {
    e.preventDefault();
    const city = !!e.target.elements.city && e.target.elements.city.value;
    if (!city) {
      return;
    }

    const api=await fetch(`http://api.openweathermap.org/data/2.5/weather?q=${city}&units=metric&appid=563f12881628bc03a04f230c259dd4f9`);
    const rtr = await api.json();
   this.setState({
     temperature:rtr.main.temp,
     humidity:rtr.main.humidity,
     city:rtr.name,
     country:rtr.sys.country
   });
  }

未处理的拒绝（TypeError）：无法读取const city的未定义错误的属性“值”

1 个答案: