async function should have await expression JS-0116async function without any await expressions327 .post("/user/verify-email", {
328 email: recovery_email,
329 })
330 .then(async (response) => {331 toast.success(response.data.message);332 setProfile({333 ...profile,334 okforSecurityInfo2: false,335 });336 })337 .catch((error) => {
338 toast.error(error.response.data.message);
339 setProfile({async function without any await expressions301 .post("/user/verify-email", {
302 email,
303 })
304 .then(async (response) => {305 toast.success(response.data.message);306 setProfile({307 ...profile,308 okforPersonalInfo2: false,309 });310 })311 .catch((error) => {
312 toast.error(error.response.data.message);
313 setProfile({async function without any await expressions303 .post("/user/verify-email", {
304 email,
305 })
306 .then(async (response) => {307 toast.success(response.data.message);308 setProfile({309 ...profile,310 okforPersonalInfo2: false,311 });312 })313 .catch((error) => {
314 toast.error(error.response.data.message);
315 setProfile({async function without any await expressions329 .post("/user/verify-email", {
330 email: recovery_email,
331 })
332 .then(async (response) => {333 toast.success(response.data.message);334 setProfile({335 ...profile,336 okforSecurityInfo2: false,337 });338 })339 .catch((error) => {
340 toast.error(error.response.data.message);
341 setProfile({A function that does not contain any await expressions should not be async (except for some edge cases
in TypeScript which are discussed below).
Asynchronous functions in JavaScript behave differently than other functions in two important ways:
- The return value is always a
Promise. - You can use the
awaitoperator inside them.
Functions are made async so that we can use the await operator inside them.
Consider this example:
async function fetchData(processDataItem) {
const response = await fetch(DATA_URL);
const data = await response.json();
return data.map(processDataItem);
}
Asynchronous functions that don't use await might be an unintentional result of refactoring.
Note: This issue ignores async generator functions.
Generators yield rather than return a value and async generators might yield all the values of another async generator without ever actually needing to use await.
In TypeScript, one might feel the need to make a function async to comply with type signatures defined by an interface.
Ideally, the code should be refactored to get rid of such restrictions, but sometimes that isn't feasible
(For example, when we are implementing an interface defined in a 3rd party library like Next.js).
This situation can easily be circumvented by returning the value with a call to Promise.resolve:
interface HasAsyncFunc {
getNum: () => Promise<number>
}
// Not recommended:
const o: HasAsyncFunc = {
async getNum() { return 1 }
}
// Recommended:
const o: HasAsyncFunc = {
// We only use `Promise.resolve` to adhere to the type
// of the surrounding object.
getNum() { return Promise.resolve(1) }
}
It is also advised to add a comment near the redundant promise to make the intent clear.
Bad Practice
async function fetchData(): string {
// `readFileSync` is a synchronous function that blocks
// the main thread, and thus does not need to be `await`ed
return fs.readFileSync("data.txt", "utf-8");
}
performAction(async () => { console.log("no awaits in here") });
Recommended
async function fetchDataAsync(): Promise<string> {
return await fs.readFile("data.txt", "utf-8")
}
performAction(async () => { await writeToFile(data) });
// Allow empty functions.
async function no_op() {}