Check if hook exists and don't reinstall.

index.js

@@ -10,13 +10,14 @@ module.exports = function (__dirname) {
 			return preuninstall(__dirname);
 		}
 	};
-}
+};
 
 var fs = require('fs');
 var os = require('os');
 var path = require('path');
 var util = require('util');
 var mkdirp = require('mkdirp');
+var glob = require('glob');
 
 function generateHookName(pkg, hook) {
 	return pkg.name + '.js';
@@ -57,17 +58,28 @@ function forEachHook(pkgdir, callback) {
 
 	if (ns.hooks) {
 		ns.hooks.forEach(function (hook) {
-			callback(hooksDir, pkg, hook)
+			callback(hooksDir, pkg, hook);
 		});
 	}
 }
 
+function hookInstalled(hookDir, pkg, hook) {
+	var hookBaseName = pkg.name;
+	var hookGlob = path.join(hookDir, "*" + hookBaseName + "*");
+	var files = glob.sync(hookGlob);
+	return files.length > 0;
+}
+
 function postinstall(pkgdir) {
 	forEachHook(pkgdir, function (hooksDir, pkg, hook) {
 		var hookDir = path.join(hooksDir, hook.type);
 		if (!fs.existsSync(hookDir)) {
 			mkdirp.sync(hookDir);
 		}
+		if (hookInstalled(hookDir, pkg, hook)) {
+			console.log('Hook already installed: ' + pkg.name);
+			return;
+		}
 		var hookFileName = generateHookName(pkg, hook);
 		var hookPath = path.join(hookDir, hookFileName);
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "nativescript-hook",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Helper module for installing hooks into NativeScript projects",
   "main": "index.js",
   "scripts": {
@@ -13,6 +13,7 @@
     "url": "https://github.com/NativeScript/nativescript-hook.git"
   },
   "dependencies": {
+    "glob": "^6.0.1",
     "mkdirp": "^0.5.1"
   }
 }