如何在 async-await 中手动触发拒绝

Question

I have worked with Promises in Javascript and I am trying to implement my functions in async-await . How do I trigger a reject() which will be caught in .catch() in async-await

In promises we have a way to manually trigger a reject() :

const doSomething = (someNumber)=>{
    return new Promise((resolve,reject)=>{
    if (someNumber > 5) {
        resolve('this resolves when someNumber is greater than 5')
    }else{
        reject('this gives a reject when someNumber is not greater than 5')
    }

    })
}

doSomething(7)
.then((infoMessage)=>{
    //this will show
    console.log(infoMessage)
})
.catch((err)=>{
    //this wont show
    console.log(errMessage)
})

doSomething(3)
.then((infoMessage)=>{
        //this wont show
    console.log(infoMessage)
})
.catch((err)=>{
        //this will show
    console.log(errMessage)
})

Answer 1

Just throw the error:

async function rejectMe() {
   throw new Error("rejected!");
}

async function main() {
  await rejectMe();
}

main()
.then(() => {
  console.log("finished!")
})
.catch((e) => {
  console.error(e);
})

Answer 2

Promise.reject()在承诺链中的任何地方都应该这样做。

Answer 3

Have it this way:

const doSomething = (someNumber)=>{
if (someNumber > 5) {
    return Promise.resolve('this resolves when someNumber is greater than 5')
}
else
  {
    return Promise.reject('this gives a reject when someNumber is not greater than 5')
  }
})