WebAssembly

• Getting Started
• API Reference

Getting Started

Basic Setup

1. Include wasm_exec.js to your web app

   <Script src="wasm_exec.js"/>

2. Add following code to check the WebAssembly compatibility:

   if (WebAssembly) {
   	// WebAssembly.instantiateStreaming is not currently available in Safari
   	if (WebAssembly && !WebAssembly.instantiateStreaming) { // polyfill
   		WebAssembly.instantiateStreaming = async (resp, importObject) => {
   			const source = await (await resp).arrayBuffer();
   			return await WebAssembly.instantiate(source, importObject);
       };
   	} 
   }

3. Instantiate and attach a __gobridge__ object to the global object, DMSCrypto will hook and exports all available function to the __gobridge__ object

   const g = global || window || self;
      
   if (!g.__gobridge__) {
   	g.__gobridge__ = {};
   }

4. Use WebAssembly.instantiateStreaming to load and instantiate the DMSGoCrypto.wasm library:

   const go = new Go(); // Go provided by the wasm_exec.js to run the GoWasm library
   WebAssembly.instantiateStreaming(fetch("DMSGoCrypto.wasm"), go.importObject).then((result) => {
   		go.run(result.instance); // ** NOTE: Call go.run() before using any WebAssembly function **
   		__gobridge__.generateSecp256k1Key("", (err, privKey) => {
   			if (err != null) {
   				console.log(err);
   			} else {
   				console.log(privKey);
   			}
   	});
   });

API Reference

Overall API Design

Due to restriction of Go-WebAssembly, all DMSCrypto WebAssembly API is designed to provide a Parameters + Callback function signature pattern.

Take generateSecp256k1Key as the example:

__gobridge__.generateSecp256k1Key(
  // First param would be an object, check each API spec for the definition 
  "", 
  
  // Final param would always be a callback in which the first param is a nullable `error`
  (err, privKey) => {
		if (err != null) {
			console.log(err);
		} else {
			console.log(privKey);
		}
});