async函数总是返回Promise。由于componentDidMount没有设计/记录为async函数，因此 React 不会对其返回的Promise做任何事情。async如果您为此使用函数，请确保将其所有代码包装在try/中catch，以便捕获所有错误并且您不会最终遇到未处理的异常（这将成为未处理的拒绝）。

问题是您试图await在非async函数中使用：您传递的回调then。使用async/await时，您几乎从不使用then. 反而：

async componentDidMount() {
  try {
    const location = await this.geoLocation.getAddress();
    if (location.address != null && location.error != "undefined") {
      const data = await this.getFifteenMinsData(y, x);
      let fifteenMins = data["forecasts"];
      console.log(fifteenMins);
    } 
  } catch (err) {
      // Do something with the fact an error occurred
  }
}

componentDidMount或者通过使用 IIFE避免返回Promise：

componentDidMount() {
  (async () => {
    const location = await this.geoLocation.getAddress();
    if (location.address != null && location.error != "undefined") {
      const data = await this.getFifteenMinsData(y, x);
      let fifteenMins = data["forecasts"];
      console.log(fifteenMins);
    } 
  })()
  .catch(error => {
    // Do something with the fact an error occurred
  });
}

或者根本不使用async函数（但async函数真的很方便）：

componentDidMount() {
  this.geoLocation.getAddress()
    .then(location => {
      if (location.address != null && location.error != "undefined") {
        return this.getFifteenMinsData(y, x)
          .then(data => {
            let fifteenMins = data["forecasts"];
            console.log(fifteenMins);
          });
      } 
    })
    .catch(error => {
      // Do something with the fact an error occurred
    });
}

旁注：这对线：

const data = await this.getFifteenMinsData(y, x);
let fifteenMins = data["forecasts"];

如果你愿意，可以这样写，将结果解构到fifteenMins变量中：

let {fifteenMins: forecasts} = await this.getFifteenMinsData(y, x);

同样，如果您确实决定使用非async版本，您可以在then处理程序的参数列表中执行此操作：

.then(({fifteenMins: forecasts}) => {
  console.log(fifteenMins);
});

如果你正在使用 await 你不必使用 then

let data=  await this.getFifteenMinsData(y, x);

编辑

let location = await this.geoLocation.getAddress();
  //do your stuff
  if (location.address != null && location.error != "undefined") {
    let fifteenMins = [];
    let data = await this.getFifteenMinsData(y, x);
    fifteenMins = data["forecasts"];
      console.log(fifteenMins);
  }