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WebAssembly with AssemblyScript

note
  • AssemblyScript was designed for WebAssembly and has a syntax similar to TypeScript.
  • Support for WASI is uncertain, given that the AssemblyScript team has criticized the WASI standardization process.

Install AssemblyScript​

To install AssemblyScript on your local system, run the command:

npm install -g assemblyscript

We also need to install as-wasi. It is an easy to use API for the AssemblyScript WASI bindings. By bindings, we mean the declared functions that would map to the WASI host functions. The command to do the same is:

npm install --save as-wasi

AssemblyScript code​

The fibonacci code in AssemblyScript is:

import "wasi";

export function fibo(n: i32): i32 {
  if (n == 0 || n == 1) return n;
  return fibo(n - 1) + fibo(n - 2);
}

let res = fibo(7);
console.log(res.toString());
tip

Access the AssemblyScript codex repository for code samples, including the fibonacci example.

We need to import wasi to add some nice defaults for compiling to WASI and we need to import Console to write to stdout.

Compile AssemblyScript code to Wasm​

To compile your AssemblyScript code, simply run:

asc fibo.ts -o fibo.wasm

Run with Enarx​

enarx run fibo.wasm