Benchmark: then vs. async-await

Tests:

then
function one() { return new Promise((resolve, reject) => { return resolve(`hi`); }); } function khw() { one().then((message) => console.log(message)); } khw();
async-await
function one() { return new Promise((resolve, reject) => { return resolve(`hi`); }); } async function khw() { console.log(await one()); } khw();

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Firefox 11 runs

then

647K/s

async-await

318K/s

Fastest: then (2.0x faster)

View exact numbers

✓ then: 647,046 ops/sec
• async-await: 318,048 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
then
async-await

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:143.0) Gecko/20100101 Firefox/143.0

Browser/OS: Firefox 143 on Windows

View result in a separate tab

then

809K/s

async-await

658K/s

View exact numbers

Test name	Executions per second
✓ then	809,302 Ops/sec
async-await	657,978 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

**Understanding the Benchmark**

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net. The benchmark tests two different approaches to handling promises in JavaScript: the traditional `then` method and the newer `async/await` syntax.

**Test Cases**

The test cases are as follows:

1. **"then"`**: This test case uses the traditional `then` method to handle a promise returned by the `one()` function. The `one()` function returns a promise that resolves with the string "hi". The `khw()` function calls `one()` and logs the result using `console.log()`.
2. **"async-await"`**: This test case uses the newer `async/await` syntax to handle a promise returned by the `one()` function. The `one()` function returns a promise that resolves with the string "hi". The `khw()` function calls `one()` and logs the result using `console.log()`, but this time using `await` instead of `.then()`.

**Comparison**

The benchmark compares the performance of these two approaches:

* **Pros of then**: This method is widely supported by older browsers and has been the de facto standard for handling promises. It's also a good learning experience, as it helps developers understand how promises work.
* **Cons of then**: The `then` method can lead to callback hell, where nested callbacks can make code harder to read and maintain. This approach can also be error-prone, especially when dealing with multiple promise chains.

**Pros of async/await**

* **Benefits of async/await**: This syntax is more modern and easier to read than the `then` method. It reduces the risk of callback hell and makes code more concise.
* **Cons of async/await**: This syntax is only supported by newer browsers, which may lead to compatibility issues in older environments.

**Library**

There are no libraries used in these test cases.

**Special JS Feature/Syntax**

The `async` and `await` keywords are special features introduced in ECMAScript 2017 (ES7). They allow developers to write asynchronous code that's more readable and easier to maintain. The `await` keyword is a shorthand for `then()` with `.catch()`, which makes it easier to handle promises.

**Other Alternatives**

If you prefer the `then` method or want to support older browsers, you can use alternative approaches like:

* **Promise.prototype.then()**: This method allows you to chain promises together using the `then()` method.
* **Promise.prototype.catch()**: This method allows you to handle errors in promise chains using the `catch()` method.

However, if you're targeting modern browsers and want to take advantage of async/await syntax, it's generally recommended.

then vs. async-await (version: 0) Benchmark.js

Comparing performance of: `then vs async-await`

Created: 4 years ago by: Guest

Go to the latest result

then

async-await

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Firefox 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

then vs. async-await (version: 0) Benchmark.js

Comparing performance of: then vs async-await

Created: 4 years ago by: Guest

Go to the latest result

then

async-await

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Firefox 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Comparing performance of: `then vs async-await`