SyntaxError：“await”仅在“async”中有效 function - 需要帮助

Question

So, I am building a Bot (Specifically for Discord) and I am very new to JavaScript, and coding in general.

I was watching a tutorial about a purging messages from an area command (You tell the bot how many messages to delete, and it does so.)

Everything was going swimmingly, I had worked for almost an hour on this command, and after I saved and ran the "bot" in my CMD, I got this error (Shown in the error section, and expected results area)

Basically:

const fetched = await message.channel.fetchMessages({limit: args[0]});

SyntaxError: await is only valid in async function

But I am pretty sure it is an async function, I am still very new to coding so I may have closed it off or something, not sure.

FYI in line 31 I thought I "turned on" an async thing, but maybe I closed it.

I didn't send the complete code.

As I am very new to coding, I couldn't really do much. I did add an ";" (without the quotes) which solved one error, but not the one I am asking about.

// Purge messages command.
if (msg.startsWith(prefix + 'PURGE')) { // COmmand checks like "!PING", but ``startWith`` because you'll be adding a number.
  // Wrapping in an async because ``awaits`` only work in asyncs.
  async function purge() {
    message.delete(); // Deletes command trigger, to clean up the chat more fully.

    //Now, we want to check if the user has the `Moderator` role.
    if (!message.member.roles.find("name", "Moderator")) { // This checks to see if they DONT have that role (the "!" inverts the true/false)
      message.channel.send('You need the Moderator role to use this command!');
      return; // This returns the code, so the rest doesn't run.
    }
  }
  // Check if the argument is a number.
  if (isNaN(args[0])) {
    // Posts that the message is NaN (not a number)
    message.channel.send('Your argument was not a number. \n Usage:  ' + 
      prefix + 'purge  <amount>'); //\n turns into a new line.
    // Stops the actions, so it doesn't start deleting messages.
    return;
  }

  const fetched = await message.channel.fetchMessages({limit: args[0]}); // This takes the argument number.

Expected Result: Bot turns on and deletes a bulk number of specified messages.

Complete Error Message:

C:\Users\xxxx\OneDrive\Desktop\Xxxxx xxx\xxx.js:49 const fetched = await message.channel.fetchMessages({limit: args[0]}); // This takes the argument number.

SyntaxError: await is only valid in async function at Module._compile (internal/modules/cjs/loader.js:723:23) at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10) at Module.load (internal/modules/cjs/loader.js:653:32) at tryModuleLoad (internal/modules/cjs/loader.js:593:12) at Function.Module._load (internal/modules/cjs/loader.js:585:3) at Function.Module.runMain (internal/modules/cjs/loader.js:831:12) at startup (internal/bootstrap/node.js:283:19) at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

Answer 1

You have to mark your method as async .

Examples from Mozilla's async function .

async function asyncCall() {
  console.log('calling');
  var result = await resolveAfter2Seconds();
  console.log(result);
  // expected output: 'resolved'
}

var parallel = async function() {
  console.log('==PARALLEL with await Promise.all==');

  // Start 2 "jobs" in parallel and wait for both of them to complete
  await Promise.all([
      (async()=>console.log(await resolveAfter2Seconds()))(),
      (async()=>console.log(await resolveAfter1Second()))()
  ]);
}

Answer 2

Your last fetch needs to be wrapped in an async function in order to use await . Either than or you need to utilize then to resolve the promise.

const getData = async (arg) => {
    const data = await message.channel.fetchMessages({limit: args})
    return await data.json()
}

With that example you'd have to resolve getData , which means you'd either have to use then or wrap its context in async -- so wrap it in an async function.

Or:

 message.channel.fetchMessages({limit: args[0]})
    .then(response => response.json())
    .then(data => {
    /* do something here */
})

Answer 3

I couldn't understand all about your code. but I think you should add "async" top of that function.

async function func() {
    await ~
}

modify your code like that style