Async Function Without Own Await

ID

javascript.require_await

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

JavaScript

Tags

async, code-style

Description

Reports async functions whose body contains no await expression that belongs to that function. The async keyword wraps the return value in a Promise and forces a microtask hop on every call; when nothing inside the function actually awaits, that overhead has no purpose.

The check is scoped per function: an await inside a nested function (regular, generator or arrow) does not satisfy the outer one, since each function has its own async scope.

Rationale

// Bad — `async` adds an extra microtask, but nothing is awaited.
async function compute() {
  return 42;
}

async function fetchAndReturn() {
  return Promise.resolve(1);
}

The two functions above could be plain functions returning the value (or Promise.resolve(…​) if the contract explicitly requires a Promise). Marking them async obscures the synchronous nature of the body and pays for a microtask on every call.

Remediation

Drop the async marker, or introduce the await the function was supposed to perform.

// Good — `async` only when the body actually awaits.
async function fetchUser(id) {
  const res = await fetch(`/users/${id}`);
  return res.json();
}

// Good — synchronous body, plain function.
function compute() {
  return 42;
}

// Good — explicit promise wrapper makes intent obvious.
function asyncCompute() {
  return Promise.resolve(42);
}

References