await (async ():Type => {return value})():: error 找不到名称'await'.ts(2304)

Question

// Does not work - Cannot find name 'await'.ts(2304)
let someVariable = await (async ():someType => {
   // i need to use await inside here so i need it async
   return someValue;
})();

// does work, but not async.
let someVariable2 = (():someType => {
   // cant use await inside
   return someValue
})();

i tried wrapping await inside another set of curved brackets, still doesnt work. yes i know i can declare a function then call it like you would normally, but i'd rather have it like this. if it isnt possible then ill go back to the normal way.

i do not know fully what () does in cases like this, but im assuming it returns the object inside. is it possible to use async/await like this? if possible would also like to learn more about how () works in cases like this.

code runs on Deno
edit: people saying "await must be used inside an async block" Deno has top-level await.

Clarifying.

// this is top-level
async function somefunc() {}
await somefunc(); // this WORKS on deno.

issue is let var = await(async () => {})() creates said error, and i am trying to find a way to fix this with a other way than declaring then await it

edit: https://github.com/microsoft/TypeScript/issues/38483

Answer 1

Await has to be called inside a async function.

 const aFunc = async () =>{ let someVariable = await (async ():someType => { const someValue = await asyncFunc() return someValue; })(); // Now you get the value console.log(someVariable) } aFunc()

Now You can call aFunc function to make it work

Answer 2

await can only within an async block. Make sure outside await is also within an async block or you can save the promise within someVariable .

let someVariable = (async ():someType => {
   return someValue;
})();

someVariable.then((result) => {
 // result contains whatever u returned in the async block.
})

 const someVariable = (async () => { const result = await Promise.resolve('Hey there;') return result. })() someVariable.then(result => console.log({ result }))