is-async-function

What is is-async-function?

The is-async-function npm package is designed to help developers determine if a given function is an asynchronous function. This can be particularly useful in scenarios where the behavior of code needs to be altered based on whether a function is asynchronous or not, such as in dynamic function execution, middleware handling, or in libraries that need to support both synchronous and asynchronous operations.

What are is-async-function's main functionalities?

Checking if a function is asynchronous

This feature allows you to check if a given function is an async function. The package exports a single function that takes one argument (the function to check) and returns a boolean indicating whether the function is asynchronous. This is useful for dynamically handling functions based on their nature.

const isAsyncFunction = require('is-async-function');

async function foo() {};
console.log(isAsyncFunction(foo)); // true

function bar() {};
console.log(isAsyncFunction(bar)); // false

Other packages similar to is-async-function

is-promise

The is-promise package checks if a value is a Promise, which is a related but different check compared to is-async-function. While is-async-function checks the nature of the function itself, is-promise checks the return value of a function to determine if it's a Promise. This distinction is crucial in understanding and handling asynchronous operations in JavaScript.

kind-of

kind-of is a more general utility for checking the type of a value in JavaScript, which includes support for identifying functions and promises among many other types. Compared to is-async-function, kind-of offers a broader range of type checks but does not specifically focus on distinguishing between synchronous and asynchronous functions. It's more versatile but less specialized.

README

is-async-function

Is this a native async function?

Example

var isAsyncFunction = require('is-async-function');
assert(!isAsyncFunction(function () {}));
assert(!isAsyncFunction(null));
assert(!isAsyncFunction(function* () { yield 42; return Infinity; }));
assert(isAsyncFunction(async function () {}));

Tests

Simply clone the repo, npm install, and run npm test

Changelog

v2.1.1 - 2025-01-22

Fixed

• [Refactor] use async-function for the eval parts #31

Commits

• [Refactor] move new Function helper into a separate file db36da5
• [Dev Deps] update @arethetypeswrong/cli, @types/tape 981ab90
• [meta] add exports 81bb8e5
• [Refactor] skip getProto call when AsyncFunction does not exist dc929a5