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wasm-forge-example

A demonstration of WebAssembly integration in Forge applications.

Overview

This example shows:

  • Compiling WASM modules with runtime:wasm
  • Instantiating and calling WASM functions
  • Memory read/write operations
  • Module lifecycle management

Features

  • Compile WASM from bytes
  • Call exported functions with parameters
  • Direct memory manipulation
  • Multiple module support (add, multiply, memory ops)

Running

Terminal window
forge dev examples/wasm-forge-example

Capabilities

[capabilities.channels]
allowed = ["*"]


[capabilities.wasm]
allowed = true

Key Patterns

Compiling WASM

import { compile, instantiate } from "runtime:wasm";


// Compile from bytes
const moduleId = await compile(wasmBytes);


// Instantiate the module
const instance = await instantiate(moduleId);

Calling Functions

// Get exports
const exports = await instance.getExports();
// Returns: [{ name: "add", kind: "function" }, ...]


// Call a function
const result = await instance.call("add", 7, 5);
console.log(result[0]); // 12

Memory Operations

// Write to WASM memory
const data = new Uint8Array([1, 2, 3, 4]);
await instance.memory.write(0, data);


// Read from WASM memory
const bytes = await instance.memory.read(0, 4);


// Get memory size (in 64KB pages)
const pages = await instance.memory.size();

Module Cleanup

// Release resources when done
await instance.drop();

Example WASM Modules

Simple Add Function

(module
  (func (export "add") (param i32 i32) (result i32)
    local.get 0
    local.get 1
    i32.add))

Memory Operations

(module
  (memory (export "memory") 1)
  (func (export "get_value") (param i32) (result i32)
    local.get 0
    i32.load)
  (func (export "set_value") (param i32 i32)
    local.get 0
    local.get 1
    i32.store))

Architecture

Deno (runtime:wasm)          WebAssembly Runtime
       |                            |
       |-- compile(bytes) -------> | Parse & validate
       | <-- moduleId ------------ |
       |                            |
       |-- instantiate(id) ------> | Create instance
       | <-- instance ------------ |
       |                            |
       |-- call("add", 7, 5) ----> | Execute
       | <-- [12] ---------------- |
       |                            |
       |-- memory.write() -------> | Direct memory access
       |                            |

Extending

Load external WASM files:

import { readBytes } from "runtime:fs";


const wasmBytes = await readBytes("./my-module.wasm");
const moduleId = await compile(wasmBytes);
const instance = await instantiate(moduleId);