Pros of Emscripten

• Supports multiple languages (C, C++, etc.), not just Rust
• More mature project with a larger ecosystem and community
• Provides a more complete runtime environment, including a virtual file system

Cons of Emscripten

• Generally produces larger output files compared to wasm-bindgen
• Can be more complex to set up and use, especially for simpler projects
• May include unnecessary features for projects that don't require a full runtime environment

Code Comparison

Emscripten (C++):

#include <emscripten.h>
#include <iostream>

EMSCRIPTEN_KEEPALIVE
extern "C" void greet(const char* name) {
    std::cout << "Hello, " << name << "!" << std::endl;
}

wasm-bindgen (Rust):

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub fn greet(name: &str) {
    println!("Hello, {}!", name);
}

Both examples show how to export a simple greeting function to JavaScript. Emscripten requires explicit use of EMSCRIPTEN_KEEPALIVE and extern "C", while wasm-bindgen uses the #[wasm_bindgen] attribute for similar functionality.

Pros of Wasmer

• More versatile: Supports multiple languages and can run WebAssembly outside the browser
• Standalone runtime: Can execute Wasm modules independently without relying on a browser environment
• Advanced features: Offers memory management, caching, and cross-compilation capabilities

Cons of Wasmer

• Steeper learning curve: Requires more setup and configuration compared to wasm-bindgen
• Larger footprint: Generally has a bigger size and resource usage due to its comprehensive features
• Less focused on JavaScript interop: Not as streamlined for web-specific use cases as wasm-bindgen

Code Comparison

wasm-bindgen:

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

Wasmer:

use wasmer::{imports, Instance, Module, Store};

let module = Module::from_file(&store, "add.wasm")?;
let instance = Instance::new(&module, &imports! {})?;
let add = instance.exports.get_function("add")?;
let result = add.call(&[Value::I32(5), Value::I32(37)])?;

This comparison highlights the simplicity of wasm-bindgen for web-focused projects, while Wasmer offers more flexibility and power for broader WebAssembly use cases.

Pros of AssemblyScript

• Easier learning curve for JavaScript developers
• Supports a subset of TypeScript syntax
• Faster compilation times compared to Rust

Cons of AssemblyScript

• Less mature ecosystem and tooling
• Limited access to low-level optimizations
• Smaller community and fewer resources

Code Comparison

AssemblyScript:

export function add(a: i32, b: i32): i32 {
  return a + b;
}

wasm-bindgen (Rust):

use wasm_bindgen::prelude::*;

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

Key Differences

• AssemblyScript uses TypeScript-like syntax, making it more familiar to JavaScript developers
• wasm-bindgen requires Rust knowledge but offers more low-level control and optimization possibilities
• AssemblyScript has a simpler setup process, while wasm-bindgen requires additional Rust tooling
• wasm-bindgen benefits from Rust's strong type system and memory safety features
• AssemblyScript compilation is generally faster, but wasm-bindgen produces more optimized WebAssembly code

Both projects aim to simplify WebAssembly development, but they cater to different developer preferences and use cases. AssemblyScript is more accessible for web developers, while wasm-bindgen leverages Rust's performance and safety features.

Pros of wabt

• Language-agnostic: Works with multiple programming languages, not limited to Rust
• Comprehensive toolset: Includes assembler, disassembler, and other utilities for WebAssembly
• Lower-level control: Provides more direct manipulation of WebAssembly modules

Cons of wabt

• Steeper learning curve: Requires more in-depth knowledge of WebAssembly internals
• Less automated: Manual handling of JavaScript interop and memory management
• Limited high-level abstractions: Focuses on low-level WebAssembly operations

Code Comparison

wabt (C++):

#include <cstdio>
#include "src/binary-reader.h"
#include "src/error-formatter.h"

void ReadBinaryFile(const char* filename) {
  // Implementation details
}

wasm-bindgen (Rust):

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

The wabt example shows low-level binary reading, while wasm-bindgen demonstrates high-level JavaScript interop.

Pros of wasmtime

• Broader scope: Wasmtime is a general-purpose WebAssembly runtime, supporting various languages and use cases beyond just Rust-to-WebAssembly interop
• Standalone execution: Can run WebAssembly modules directly, without requiring a web browser or JavaScript environment
• Performance-focused: Implements advanced optimization techniques for faster WebAssembly execution

Cons of wasmtime

• Higher complexity: As a full runtime, it may be more complex to set up and use compared to wasm-bindgen's focused approach
• Less integrated with Rust: Doesn't provide the same level of seamless Rust-to-WebAssembly integration as wasm-bindgen

Code comparison

wasm-bindgen:

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

wasmtime:

let engine = Engine::default();
let module = Module::from_file(&engine, "add.wasm")?;
let instance = Instance::new(&mut store, &module, &[])?;
let add = instance.get_func(&mut store, "add")?;
let result = add.call(&mut store, &[Val::I32(1), Val::I32(2)])?;

This comparison highlights the different approaches: wasm-bindgen focuses on seamless Rust-to-WebAssembly integration, while wasmtime provides a more general-purpose runtime for executing WebAssembly modules.