JavaScript and WebAssembly should be a joy to use together.
This project aims to provide a simple, easy to learn, technology-agnostic way bridge the two worlds.
Use any WebAssembly programming language out of the box:
See a demo of it working!
Load WebAssembly like JavaScript.
<html>
<head>
<meta charset="utf-8">
<script src="https://unpkg.com/js-wasm/js-wasm.js"></script>
<script type="application/wasm" src="helloworld.wasm"></script>
</head>
<body>
...
</body>
</html>Create JavaScript functions and invoke them
[dependencies]
js = "0.2"let fn_log = js!(
"function(strPtr,strLen){
console.log(this.readUtf8FromMemory(strPtr,strLen));
}");
let msg = "Hello World!";
fn_log.invoke_2(msg.as_ptr() as u32, msg.len() as u32);import {js_register_function,js_invoke_function} from "./js-wasm"
let console_log_fn:f64 = 0;
export function console_log(msg: string) : void {
if(console_log_fn === 0){
const code = "function(msgPtr,msgLen){ console.log(this.readUtf16FromMemory(msgPtr,msgLen)); }";
console_log_fn = <f64>js_register_function(<f64>changetype<usize>(code),<f64>code.length*2, 16);
}
js_invoke_2(<f64>console_log_fn,<f64>changetype<usize>(msg),<f64>msg.length*2);
}
export function main():void {
console_log("Hello World!");
}#include "js-wasm.h"
char *code = "function(context,cstrPtr){\
console.log(this.getCStringFromMemory(cstrPtr));\
}";
JSFunction fnLog = js_register_function(code,strlen(code));
js_invoke_function_2(fnLog, "Hello World!");In your JS function context this contains several functions handle most issues you'll encounter
| Name | Description |
|---|---|
readUtf8FromMemory(start,length) |
Extract utf-8 text from your program's memory. |
writeUtf8ToMemory(str) |
Write utf-8 to a memory location you are sure it should go. |
readCStringFromMemory(start,length) |
Extract C string text from your program's memory. |
writeCStringToMemory(str) |
Write C string to a memory location you are sure it should go. |
readUtf16FromMemory(start,length) |
Extract utf-16 text from your program's memory. |
writeUtf16ToMemory(str) |
Write utf-16 to a memory location you are sure it should go. |
readUint8ArrayFromMemory(start) |
Read a list of uint8 from a pointer to a location of a number of elements, followed by a pointer to bytes in memory. |
storeObject(object) |
Store an object in your context for later reference, get a handle you can give to WebAssembly. |
getObject(handle) |
Retreive and object from your context with a handle. |
releaseObject(handle) |
Release a stored object so it's memory can be freed. |
module |
Get access to your program so you can call methods on it. |
My name is RICHΛRD ΛNΛYΛ, i'm a technologist from Portland, OR. I love the potential WebAssembly has for bringing powerful experiences to the world!
This project is licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in js-wasm by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.