Demo Svelte + Rust

👉 You can play around the live demo here

Create a Svelte app

Everything you need to build a Svelte project, powered by create-svelte.

Creating a project

If you're seeing this, you've probably already done this step. Congrats!

# create a new project in the current directory
npm create svelte@latest

# create a new project in my-app
npm create svelte@latest my-app

Developing

Once you've created a project and installed dependencies with npm install (or pnpm install or yarn), start a development server:

npm run dev

# or start the server and open the app in a new browser tab
npm run dev -- --open

Building

To create a production version of your app:

npm run build

You can preview the production build with npm run preview.

To deploy your app, you may need to install an adapter for your target environment.

Add some Rust 🦀 to your Svelte app

Install Rust by going to the Install Rust page and following the instructions.

Install wasm-pack

cargo install wasm-pack

Create a new Rust package

cargo new --lib my-package

Write a Rust function

// my-package/src/lib.rs

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

Specify the version of the package

By adding crate-type = ["cdylib"]

[package]
name = "my-package"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
wasm-bindgen = "0.2.87"

[lib]
crate-type = ["cdylib"]

Build your Rust package

cd my-package
wasm-pack build --target web

Pick the generated pkg folder generated in my-package

And drop it in the /lib folder of your Svelte app

Import your Rust package in your Svelte app

// src/routes/+page.svelte

import init, { add } from "$lib/pkg/my_package";

onMount(async () => {
    await init();
});

function handleClick(): void {
    result = add(numberA, numberB);
}