nodejs WebAssembly basic example

compile.sh

# emcc (Emscripten gcc/clang-like replacement) 1.37.22 ()
emcc -o index.js hello4.c -O3 -s WASM=1 -s NO_EXIT_RUNTIME=1 -s SIDE_MODULE=1

hello4.c

#include <emscripten/emscripten.h>

int main(int argc, char ** argv) {
}

#ifdef __cplusplus
extern "C" {
#endif

EMSCRIPTEN_KEEPALIVE
int doubler(int x) {
  int z = 2 * x;
  return z;
}

#ifdef __cplusplus
}
#endif

nodetest.js

// nodejs v8.9.3

'use strict';

const env = {
  memoryBase: 0,
  tableBase: 0,
  memory: new WebAssembly.Memory({initial: 256}),
  table: new WebAssembly.Table({initial: 0, element: 'anyfunc'})
};
const code = require('fs').readFileSync('index.wasm');
WebAssembly.instantiate(code, {env}).then(mod => {
  console.log('DOUBLER', mod.instance.exports._doubler(7));
});