Today we gonna navigating into some ways to use Rust on typescript projects with WASM.
First, we gonna create a new Rust project and navigate into it:
mkdir wasm-calc && \
cd wasm-calc && \
cargo new --lib rust-calcOpen the project in your preferred IDE. Replace the contents of lib.rs with the following code:
pub fn sum(left: i32, right: i32) -> i32 {
left + right
}
pub fn subtract(left: i32, right: i32) -> i32 {
left - right
}
pub fn multiply(left: i32, right: i32) -> i32 {
left * right
}
pub fn divide(left: i32, right: i32) -> i32 {
left / right
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn it_works() {
let result = sum(2, 2);
assert_eq!(result, 4);
}
#[test]
fn test_subtract() {
let result = subtract(2, 2);
assert_eq!(result, 0);
}
#[test]
fn test_multiply() {
let result = multiply(2, 2);
assert_eq!(result, 4);
}
#[test]
fn test_divide() {
let result = divide(2, 2);
assert_eq!(result, 1);
}
}Next, we gonna prepare the crate to be exported as WebAssembly (Wasm) by adding wasm-bindgen, a crate that provides facilities to generate bindings to javascript.
cargo add wasm-bindgenModify the Cargo.toml to include the crate-type = ["cdylib"], this is a instruction to rust compiler to work in a way that generates artifacts compatible with WASM. Ref
[lib]
crate-type = ["cdylib"]Update lib.rs to use wasm_bindgen:
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
pub fn sum(left: i32, right: i32) -> i32 {
left + right
}
#[wasm_bindgen]
pub fn subtract(left: i32, right: i32) -> i32 {
left - right
}
#[wasm_bindgen]
pub fn multiply(left: i32, right: i32) -> i32 {
left * right
}
#[wasm_bindgen]
pub fn divide(left: i32, right: i32) -> i32 {
left / right
}Now, build the package using wasm-pack, a crate that helps to build wasm to the different javascript environments.
wasm-pack build --out-dir target/pkg-node --target nodejsCreate a new Node.js project:
cd ../ && \
mkdir node-rust-calc && \
cd node-rust-calc && \
npm init -y && \
npm add typescript -D && \
npx tsc --init && \
touch index.tsAdd the Rust package as a dependency:
npm add ../rust-calc/target/pkg-nodeImport and use the Rust functions in index.ts:
import { sum, divide, multiply, subtract } from "rust-calc";
console.log("1 + 2: ", sum(1, 2)); // 3
console.log("1 - 2: ", subtract(1, 2)); // -1
console.log("1 * 2: ", multiply(1, 2)); // 2
console.log("1 / 2: ", divide(1, 2)); // 0Run the Node.js application:
npx tsc && node index.jsThats it, its really easy to use Rust with nodeJs, almost looks like magic.
Build the WebAssembly package for web targets:
cd ../rust-calc
wasm-pack build --out-dir target/pkg-web --target webHere we generated a different pkg, pkg-web as the target web differs a little from the target nodejs, so we can differ when importing them on the respective projects
Create a new project for the web:
cd ../ && \
mkdir vanilla-js-rust-calc && \
cd vanilla-js-rust-calc && \
touch index.htmlCreate an index.html file with the following content:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>Vanilla JS Rust Calc</title>
</head>
<body>
<h1>Vanilla JS Rust Calc</h1>
<p>Open the console to see the output</p>
<script type="module">
import init, {
sum,
subtract,
multiply,
divide,
} from "../rust-calc/target/pkg-web/rust_calc.js";
async function run() {
await init();
console.log("1 + 2: ", sum(1, 2)); // 3
console.log("1 - 2: ", subtract(1, 2)); // -1
console.log("1 * 2: ", multiply(1, 2)); // 2
console.log("1 / 2: ", divide(1, 2)); // 0 As the rust function is working with integers, we gonna receive 0 instead of 0.5
}
run();
</script>
</body>
</html>Serve the index.html file using a simple server like miniserve, we can't open directly the index.html with our browsers, because the WASM needs to be loaded, and when opening directly, we receive a cors when getting the WASM file
cd ../
miniserve . --index "vanilla-js-rust-calc/index.html" -p 8080Open http://localhost:8080 in your browser and check the console.
Thats it, on the vanilla we need to manually init the WASM before use it, while on nodeJs we just plug and play, what happens is that on NodeJs the WASM is initialized under the hood with direct access to the file system that node has.
Create a new Next.js project:
npx create-next-app@14.2.4 nextjs-rust-calc --use-npmNavigate to the project directory and add the Rust package:
cd nextjs-rust-calc && \
npm add ../rust-calc/target/pkg-webReplace the content of page.tsx with:
import { sum, subtract, multiply, divide } from "rust-calc";
export default function Home() {
console.log("1 + 2: ", sum(1, 2)); // 3
console.log("1 - 2: ", subtract(1, 2)); // -1
console.log("1 * 2: ", multiply(1, 2)); // 2
console.log("1 / 2: ", divide(1, 2)); // 0 As the rust function is working with integers, we gonna receive 0 instead of 0.5
return (
<main>
<h1>NextJs Rust Calc</h1>
</main>
);
}This code won't work, because as we saw on the Vanilla JS example, using the web build, we need to initialize the WASM first, so lets do this.
Modify page.tsx as follows:
"use client";
import { useEffect } from "react";
import init, { sum, subtract, multiply, divide } from "rust-calc";
export default function Home() {
useEffect(() => {
(async () => {
await init();
console.log("1 + 2: ", sum(1, 2)); // 3
console.log("1 - 2: ", subtract(1, 2)); // -1
console.log("1 * 2: ", multiply(1, 2)); // 2
console.log("1 / 2: ", divide(1, 2)); // // 0 As the rust function is working with integers, we gonna receive 0 instead of 0.5
})();
}, []);
return (
<main>
<h1>NextJs Rust Calc</h1>
</main>
);
}As the WASM initialization is an asynchronous process, i put it inside a useEffect Hook. There is a possible problem with this approach, at some point someone may try to use the rust-calc functions without the proper initialization, so, lets do a workaround to make sure that the WASM is always initialized when some of its functions is called.
We gonna create a TS package wrapping the WASM and exporting all functions only after the initialization
Lets create our typescript package:
cd ../ && \
mkdir ts-calc && \
cd ts-calc && \
npm init -y && \
npm add typescript -D && \
npx tsc --init && \
touch index.tsIn tsconfig.json, set "declaration": true, and in package.json, add "types": "index.d.ts".
Add the Rust package as a dependency:
npm add ../rust-calc/target/pkg-webCreate index.ts with the following content:
import * as rustCalc from "rust-calc";
export const instantiate = async () => {
const { default: init, initSync: _, ...lib } = rustCalc;
await init();
return lib;
};
export default instantiate;Compile the TypeScript project:
npx tscIn your Next.js project, remove the direct Rust package dependency and add the TypeScript wrapper:
cd ../nextjs-rust-calc && \
npm remove rust-calc && \
npm add ../ts-calcUpdate page.tsx to use the wrapper:
"use client";
import { useEffect } from "react";
import { instantiate } from "ts-calc";
export default function Home() {
useEffect(() => {
(async () => {
const { divide, multiply, subtract, sum } = await instantiate();
console.log("1 + 2: ", sum(1, 2)); // 3
console.log("1 - 2: ", subtract(1, 2)); // -1
console.log("1 * 2: ", multiply(1, 2)); // 2
console.log("1 / 2: ", divide(1, 2)); // 0 As the rust function is working with integers, we gonna receive 0 instead of 0.5
})();
}, []);
return (
<main>
<h1>NextJs Rust Calc</h1>
</main>
);
}This ensures that we can only access the WASM methods after its initialization.
That's it! Now you have your WASM module running in various environments.
References: