What does 'async in a function declaration' do in a function without await?

I have a function returning a Promise, without any awaits in body. What is the difference between those two snippets, if awaiting for them seems to work the same?

export async function getTags(
  tagTypeId: number
): Promise<Tags[]> {
  return getAllPages('/tags.json', {
    tagTypeId
  });
}

export function getTags(
  tagTypeId: number
): Promise<Tags[]> {
  return getAllPages('/tags.json', {
    tagTypeId
  });
}

Calling

const tags = await getTags(tag.typeId);

>Solution :

To answer your question What does ‘async in a function declaration’ do in a function without await? the answer is nothing.

Well, almost nothing.

If your function returns a value, it gets wrapped in a Promise object:

async function myFn() {
    return 1
}

function myFn2() {
    return 1
}

console.log(myFn()) // Promise, not 1
console.log(myFn2()) // 1

So in a nut shell adding async does two things:

• It allows you to use await inside the function
• It makes sure the function always returns a Promise object.

Also async functions will not throw Errors but instead return them as a rejected Promise object:

async function fn() {
    throw new Error("My error")
}

console.log(fn()) // Promise (rejected)