asaaki/0___rust_serde_json_wasm_parcel___0.md

## 0___rust_serde_json_wasm_parcel___0.md

      
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              0___rust_serde_json_wasm_parcel___0.md
            
          
    Rust, serde-json, wasm, parcel.js

With this combination it is fairly easy to get things done in Rust and utilize it in JavaScript. Yay!

  
## Cargo.toml
[package]
name = "jane"
version = "0.1.0"

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

[dependencies]
serde = "1.0"
serde_derive = "1.0"
serde_json = "1.0"

## index.html
<html>
  <head><title>jane</title></head>
  <body>
    <script src="./index.js"></script>
    <pre id='console'>...</pre>
  </body>
</html>

## index.js
import { memory, get_data, get_data_len } from "./src/lib.rs";

const offset = get_data();
const stringBuffer = new Uint8Array(memory.buffer, offset, get_data_len());

let str = "";
for (let i = 0; i < stringBuffer.length; i++) {
  str += String.fromCharCode(stringBuffer[i]);
}

let jane = JSON.parse(str);
console.log("jane:", jane);

let div = document.getElementById('console');
div.innerText = `
  (rust string)->(JSON.parse)->(JSON.stringify)
  => ${JSON.stringify(jane)}
`;

## src_lib.rs
// file: src/lib.rs
extern crate serde;
extern crate serde_json;
#[macro_use]
extern crate serde_derive;

use std::ffi::CString;
use std::os::raw::c_char;

#[no_mangle]
pub fn get_data() -> *mut c_char {
    let s = CString::new(jane()).unwrap();
    s.into_raw()
}

#[no_mangle]
pub fn get_data_len() -> usize {
    jane().len()
}

#[derive(Serialize, Deserialize)]
struct Person {
    name: String,
    age: u8
}

fn jane() -> String {
    let jane = Person { name: "Jane".to_string(), age: 35 };
    let json = serde_json::to_string(&jane);
    json.unwrap()
}
	[package]
	name = "jane"
	version = "0.1.0"

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

	[dependencies]
	serde = "1.0"
	serde_derive = "1.0"
	serde_json = "1.0"
	<html>
	<head><title>jane</title></head>
	<body>
	<script src="./index.js"></script>
	<pre id='console'>...</pre>
	</body>
	</html>
	import { memory, get_data, get_data_len } from "./src/lib.rs";

	const offset = get_data();
	const stringBuffer = new Uint8Array(memory.buffer, offset, get_data_len());

	let str = "";
	for (let i = 0; i < stringBuffer.length; i++) {
	str += String.fromCharCode(stringBuffer[i]);
	}

	let jane = JSON.parse(str);
	console.log("jane:", jane);

	let div = document.getElementById('console');
	div.innerText = `
	(rust string)->(JSON.parse)->(JSON.stringify)
	=> ${JSON.stringify(jane)}
	`;
	// file: src/lib.rs
	extern crate serde;
	extern crate serde_json;
	#[macro_use]
	extern crate serde_derive;

	use std::ffi::CString;
	use std::os::raw::c_char;

	#[no_mangle]
	pub fn get_data() -> *mut c_char {
	let s = CString::new(jane()).unwrap();
	s.into_raw()
	}

	#[no_mangle]
	pub fn get_data_len() -> usize {
	jane().len()
	}

	#[derive(Serialize, Deserialize)]
	struct Person {
	name: String,
	age: u8
	}

	fn jane() -> String {
	let jane = Person { name: "Jane".to_string(), age: 35 };
	let json = serde_json::to_string(&jane);
	json.unwrap()
	}