Introduction
On May 7, 2026, the ClojureScript community welcomed version 1.12.145, marking a major milestone for developers by introducing support for asynchronous functions with Async/Await. This much-anticipated feature promises to simplify interaction with modern browser APIs and popular libraries while reducing code complexity.
Why Async/Await?
Async/Await has become a standard in JavaScript development, simplifying the management of asynchronous operations without the burden of nested promises. For ClojureScript, now targeting ECMAScript 2016, this is a natural progression. According to the latest Clojure survey, support for asynchronous functions topped the list of desired enhancements, underscoring the significance of this update.
A Concrete Example
Let's take a simple example to illustrate Async/Await implementation in ClojureScript:
``clojure (refer-global :only '[Promise]) (defn ^:async foo [n] (let [x (await (Promise/resolve 10)) y (let [y (await (Promise/resolve 20))] (inc y)) f (fn [] 20)] (+ n x y (f)))) ``
In this example, the foo function is marked as asynchronous, allowing the use of await to handle promises more smoothly. This greatly simplifies the code by avoiding nested callbacks.
Impact on Testing
Handling asynchronous tests also becomes simpler with the new syntax. Here's how it translates:
``clojure (deftest ^:async defn-test (try (let [v (await (foo 10))] (is (= 61 v))) (let [v (await (apply foo [10]))] (is (= 61 v))) (catch :default _ (is false)))) ``
This approach lightens the structure of tests, making the validation process more intuitive and less error-prone.
Key Benefits
- Improved Interoperability: No need for additional libraries to manage asynchronous operations.
- Simplified Code: Reduction of nested callbacks and promise chains.
- Easier Adoption: Alignment with JavaScript standards, easing adoption for new developers.
Conclusion
ClojureScript's adoption of Async/Await is a significant advancement for its community. It paves the way for smoother and more modern development, in line with current web standards. If you're ready to leverage these new capabilities to optimize your projects, let's discuss your project in 15 minutes.