tangzhongliang · January 2, 2020 03:53
diff --git a/Readme.txt b/Readme.txt
 https://my.oschina.net/yushulx/blog/1927717
 提高nodejs性能的方法有两种
 1.通过node-gyp来编译一个Node.js C/C++扩展。2.把C/C++代码编译成WebAssembly
 WebAssembly
  是跨平台的,使用与前端，如果对性能要求不太高的情况下，也可以用于后端
  耗时是c++的1-7倍，在不和js数据通信的情况下耗时接近于C
  AS本质上是静态的字节码语言，可以和jvm比较，理论上AS的性能可以追上java，并且由于AS使用的是基本特性，没有java的复杂，速度超过java也是有可能的
  也就是js兼容了静态语言和脚本语言的优点
  typescript转webassembly更加方便，所以未来typescript是主流趋势
 Node扩展
  需要在不同的平台上编译，肯定是性能最好的，在复杂应用中是WebAssembly的3倍
  c++扩展永远是最快的


diff --git a/hello-world.js b/hello-world.js
 // https://github.com/torch2424/wasm-by-example/blob/master/demo-util/
 export const wasmBrowserInstantiate = async (wasmModuleUrl, importObject) => {
  let response = undefined;

  if (!importObject) {
    importObject = {
      env: {
        abort: () => console.log("Abort!")
      }
    };
  }

  // Check if the browser supports streaming instantiation
  if (WebAssembly.instantiateStreaming) {
    // Fetch the module, and instantiate it as it is downloading
    response = await WebAssembly.instantiateStreaming(
      fetch(wasmModuleUrl),
      importObject
    );
  } else {
    // Fallback to using fetch to download the entire module
    // And then instantiate the module
    const fetchAndInstantiateTask = async () => {
      const wasmArrayBuffer = await fetch(wasmModuleUrl).then(response =>
        response.arrayBuffer()
      );
      return WebAssembly.instantiate(wasmArrayBuffer, importObject);
    };
    response = await fetchAndInstantiateTask();
  }

  return response;
 };

 const runWasmAdd = async () => {
  // Instantiate our wasm module
  const wasmModule = await wasmBrowserInstantiate("./hello-world.wasm");

  // Call the Add function export from wasm, save the result
  const addResult = wasmModule.instance.exports.add(24, 24);

  // Set the result onto the body
  document.body.textContent = `Hello World! addResult: ${addResult}`;
 };
 runWasmAdd();
diff --git a/hello-world.ts b/hello-world.ts
 //!!!!!!!!!!!!!!! asc hello-world.ts -b hello-world.wasm
 //!!!!!!!!!!!!!!! https://docs.assemblyscript.org/
 // This exports an add function.
 // It takes in two 32-bit integer values
 // And returns a 32-bit integer value.
 export function add(a: i32, b: i32): i32 {
  return a + b;
 }
diff --git a/index.html b/index.html
 <!DOCTYPE html>
 <html>
  <head>
    <meta charset="UTF-8" />
    <title>Hello World - AssemblyScript</title>
    <script type="module" src="./hello-world.js"></script>
  </head>
  <body></body>
 </html>
diff --git a/passbuffer.js b/passbuffer.js
 // way to pass data JS/WASM context
 let instance = ...;
 let myJSArray = new Float32Array(...);
 let length = myJSArray.length;
 let myWasmArrayPtr = instance.exports.allocateF32Array(length);
 let myWasmArray = new Float32Array(instance.exports.memory.buffer, myWasmArrayPtr, length);

 // Copy data in to be used by WebAssembly.
 myWasmArray.set(myJSArray);

 // Process the data in the array.
 instance.exports.processF32Array(myWasmArrayPtr, length);

 // Copy data out to JavaScript.
 myJSArray.set(myWasmArray);
	https://my.oschina.net/yushulx/blog/1927717
	提高nodejs性能的方法有两种
	1.通过node-gyp来编译一个Node.js C/C++扩展。2.把C/C++代码编译成WebAssembly
	WebAssembly
	是跨平台的,使用与前端，如果对性能要求不太高的情况下，也可以用于后端
	耗时是c++的1-7倍，在不和js数据通信的情况下耗时接近于C
	AS本质上是静态的字节码语言，可以和jvm比较，理论上AS的性能可以追上java，并且由于AS使用的是基本特性，没有java的复杂，速度超过java也是有可能的
	也就是js兼容了静态语言和脚本语言的优点
	typescript转webassembly更加方便，所以未来typescript是主流趋势
	Node扩展
	需要在不同的平台上编译，肯定是性能最好的，在复杂应用中是WebAssembly的3倍
	c++扩展永远是最快的
	// https://github.com/torch2424/wasm-by-example/blob/master/demo-util/
	export const wasmBrowserInstantiate = async (wasmModuleUrl, importObject) => {
	let response = undefined;

	if (!importObject) {
	importObject = {
	env: {
	abort: () => console.log("Abort!")
	}
	};
	}

	// Check if the browser supports streaming instantiation
	if (WebAssembly.instantiateStreaming) {
	// Fetch the module, and instantiate it as it is downloading
	response = await WebAssembly.instantiateStreaming(
	fetch(wasmModuleUrl),
	importObject
	);
	} else {
	// Fallback to using fetch to download the entire module
	// And then instantiate the module
	const fetchAndInstantiateTask = async () => {
	const wasmArrayBuffer = await fetch(wasmModuleUrl).then(response =>
	response.arrayBuffer()
	);
	return WebAssembly.instantiate(wasmArrayBuffer, importObject);
	};
	response = await fetchAndInstantiateTask();
	}

	return response;
	};

	const runWasmAdd = async () => {
	// Instantiate our wasm module
	const wasmModule = await wasmBrowserInstantiate("./hello-world.wasm");

	// Call the Add function export from wasm, save the result
	const addResult = wasmModule.instance.exports.add(24, 24);

	// Set the result onto the body
	document.body.textContent = `Hello World! addResult: ${addResult}`;
	};
	runWasmAdd();
	//!!!!!!!!!!!!!!! asc hello-world.ts -b hello-world.wasm
	//!!!!!!!!!!!!!!! https://docs.assemblyscript.org/
	// This exports an add function.
	// It takes in two 32-bit integer values
	// And returns a 32-bit integer value.
	export function add(a: i32, b: i32): i32 {
	return a + b;
	}
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="UTF-8" />
	<title>Hello World - AssemblyScript</title>
	<script type="module" src="./hello-world.js"></script>
	</head>
	<body></body>
	</html>
	// way to pass data JS/WASM context
	let instance = ...;
	let myJSArray = new Float32Array(...);
	let length = myJSArray.length;
	let myWasmArrayPtr = instance.exports.allocateF32Array(length);
	let myWasmArray = new Float32Array(instance.exports.memory.buffer, myWasmArrayPtr, length);

	// Copy data in to be used by WebAssembly.
	myWasmArray.set(myJSArray);

	// Process the data in the array.
	instance.exports.processF32Array(myWasmArrayPtr, length);

	// Copy data out to JavaScript.
	myJSArray.set(myWasmArray);