Add prebuildify and prebuild script

Author: aminya

.gitignore

@@ -21,6 +21,7 @@ coverage
 
 # Compiled binary addons (http://nodejs.org/api/addons.html)
 build/Release
+prebuilds
 
 # Dependency directory
 # https://www.npmjs.org/doc/misc/npm-faq.html#should-i-check-my-node_modules-folder-into-git

js/scripts/prebuild.js

@@ -0,0 +1,39 @@
+const {spawnSync} = require('child_process');
+
+main().catch(e => {
+  throw e;
+});
+
+async function main() {
+  console.log('Building distribution binary...'); // eslint-disable-line no-console
+
+  const prebuildArch = getNodearch(process.env.ARCH);
+
+  // napi is forward compatible so we only build for two targets (Node and Electron)
+  let prebuildScript = `prebuildify --napi --arch=${prebuildArch} -t 12.0.0 -t [email protected] --strip`;
+
+  if (process.platform == 'linux') {
+    prebuildScript = `${prebuildScript} --tag-libc`;
+  }
+
+  spawnSync(prebuildScript, {
+    shell: true,
+    stdio: 'inherit',
+    encoding: 'utf8',
+  });
+}
+
+/**
+ * @param {string | undefined} arch the given architecture
+ * @returns {string} the Node architecture to build for
+ */
+function getNodearch(arch) {
+  if (!arch) {
+    return process.arch;
+  }
+  if (arch === 'x86') {
+    return 'ia32';
+  } else {
+    return arch;
+  }
+}

js/src/index.js

@@ -1,7 +1,7 @@
 const { promises: fs } = require('fs');
 const path = require('path');
 
-const NSFW = require('../../build/Release/nsfw.node');
+const NSFW = require('../../binding');
 
 function NSFWFilePoller(watchPath, eventCallback, debounceMS) {
   const { CREATED, DELETED, MODIFIED } = nsfw.actions;

package.json

@@ -5,7 +5,8 @@
   "main": "js/src/index.js",
   "scripts": {
     "lint": "eslint js/src js/spec",
-    "test": "yarn lint && node js/scripts/test.js"
+    "test": "yarn lint && node js/scripts/test.js",
+    "prebuild": "node ./js/scripts/prebuild.js"
   },
   "repository": {
     "type": "git",
@@ -25,7 +26,8 @@
     "js/src",
     "src",
     "includes",
-    "binding.gyp"
+    "binding.gyp",
+    "prebuilds"
   ],
   "homepage": "https://github.com/axosoft/node-simple-file-watcher",
   "dependencies": {
@@ -36,7 +38,8 @@
     "eslint": "^6.8.0",
     "executive": "^1.6.3",
     "fs-extra": "^7.0.0",
-    "mocha": "^7.1.1"
+    "mocha": "^7.1.1",
+    "prebuildify": "^4.1.2"
   },
   "keywords": [
     "FileWatcher",