A TypeScript-like language for WebAssembly.

Designed for WebAssembly

AssemblyScript targets WebAssembly's feature set specifically, giving developers low-level control over their code.

Familiar TypeScript syntax

Its similarity with TypeScript makes it easy to compile to WebAssembly without learning a new language.

Right at your fingertips

Integrates with the existing Web ecosystem - no heavy toolchains to set up. Simply npm install it!

#!runtime=stub
/** Calculates the n-th Fibonacci number. */
export function fib(n: i32): i32 {
 var a = 0, b = 1
 if (n > 0) {
 while (--n) {
 let t = a + b
 a = b
 b = t
 }
 return b
 }
 return a
}

#!html
<textarea id="output" style="height: 100%; width: 100%" readonly></textarea>
<script type="module">
const exports = await instantiate(await compile(), { /* imports */ })
const output = document.getElementById('output')
for (let i = 0; i <= 10; ++i) {
 output.value += `fib(${i}) = ${exports.fib(i)}\n`
}
</script>

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