no-return-await

Disallow unnecessary return await

💡

Some problems reported by this rule are manually fixable by editor suggestions

Important

This rule was deprecated in ESLint v8.46.0. There is no replacement rule.

It is NOT recommended to use the no-return-await rule anymore because:

return await on a promise will not result in an extra microtask.
return await yields a better stack trace for debugging.

Historical context: When promises were first introduced, calling return await introduced an additional microtask, one for the await and one for the return value of the async function. Each extra microtask delays the computation of a result and so this rule was added to help avoid this performance trap. Later, ECMA-262 changed the way return await worked so it would create a single microtask, which means this rule is no longer necessary.

Rule Details

This rule warns on any usage of return await except in try blocks.

Examples of incorrect code for this rule:

Open in Playground

/*eslint no-return-await: "error"*/

async function foo() {
    return await bar();
}
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Examples of correct code for this rule:

Open in Playground

/*eslint no-return-await: "error"*/

async function foo1() {
    return bar();
}

async function foo2() {
    await bar();
    return;
}

// This is essentially the same as `return await bar();`, but the rule checks only `await` in `return` statements
async function foo3() {
    const x = await bar();
    return x;
}

// In this example the `await` is necessary to be able to catch errors thrown from `bar()`
async function foo4() {
    try {
        return await bar();
    } catch (error) {}
}
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When Not To Use It

You should not use this rule. There is no reason to avoid return await.

Version

This rule was introduced in ESLint v3.10.0.

Resources

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