add watch capability

lib/before-prepare.js

@@ -1,5 +1,11 @@
 var converter = require('./converter');
 
 module.exports = function ($logger, $projectData, $usbLiveSyncService) {
+	var liveSync = $usbLiveSyncService.isInitialized;
+	var bundle = $projectData.$options.bundle;
+	if (liveSync || bundle) {
+		return;
+	}
+
 	return converter.convert($logger, $projectData.projectDir);
 }

lib/converter.js

@@ -1,88 +1,77 @@
 exports.convert = convert;
 
+var spawn = require('child_process').spawn;
 var fs = require('fs');
 var path = require('path');
-var sass = require('node-sass');
-var glob = require('glob');
+
 
 function convert(logger, projectDir, options) {
-	return new Promise(function (resolve, reject) {
-		options = options || {};
-
-		var sassFilesPath = path.join(projectDir, 'app/**/*.scss');
-    var sassImportPaths = [
-      path.join(projectDir, 'app/'), 
-      path.join(projectDir, 'node_modules/')
-      ];
-    //console.log("SASS Import Path", sassImportPaths);
-
-		var sassFiles = glob.sync(sassFilesPath, { follow: true }).filter(function(filePath){
-			var path = filePath;
-      var parts = path.split('/');
-      var filename = parts[parts.length - 1];
-			return path.indexOf("App_Resources") === -1 && filename.indexOf("_") !== 0;
-		});
-
-    if(sassFiles.length === 0){
-      //No sass files in project; skip parsing
-      resolve();
-    } else {      
-      var i = 0;
-      var loopSassFilesAsync = function(sassFiles){
-        parseSass(sassFiles[i], sassImportPaths, function(e){
-          if(e !== undefined){
-            //Error in the LESS parser; Reject promise
-            reject(Error(sassFiles[i] + ' SASS CSS pre-processing failed. Error: ' + e));  
-          }
-
-          i++; //Increment loop counter
-
-          if(i < sassFiles.length){
-            loopSassFilesAsync(sassFiles);
-          } else {
-            //All files have been processed; Resolve promise
-            resolve();
-          }
+    return new Promise(function (resolve, reject) {
+        options = options || {};
+
+        var peerSassPath = path.join(__dirname, '../../node-sass');
+        var sassPath = path.join(peerSassPath, 'bin/node-sass');
+        var appDir = path.join(projectDir, "app");
+
+        if (fs.existsSync(sassPath)) {
+            try {
+                logger.info('Found peer node-sass');
+            } catch (err) { }
+        } else {
+            throw Error('node-sass installation local to project was not found. Install by executing `npm install node-sass`.');
+        }
+
+        var nodeArgs = [sassPath, appDir, '--output', appDir, '--output-style', 'compressed'];
+        if (options.watch) {
+            nodeArgs.push('-r', '--watch');
+        }
+
+        logger.trace(process.execPath, nodeArgs.join(' '));
+        var sass = spawn(process.execPath, nodeArgs);
+
+        var isResolved = false;
+        var watchResolveTimeout;
+        sass.stdout.on('data', function (data) {
+            var stringData = data.toString();
+            logger.info(stringData);
         });
-      }
-
-      loopSassFilesAsync(sassFiles);
-    }
-	});
-}
 
-function parseSass(filePath, importPaths, callback){
-  var sassFileContent = fs.readFileSync(filePath, { encoding: 'utf8'});
-  var cssFilePath = filePath.replace('.scss', '.css');
+        sass.stderr.on('data', function (err) {
+            var message = '';
+            var stringData = err.toString();
+            try {
+                var parsed = JSON.parse(stringData);
+                message = parsed.formatted || parsed.message || stringData;
+            } catch (e) {
+                message = err.toString();
+            }
+            logger.info(message);
+        });
 
-  if(sassFileContent.trim().length === 0) {
-    // No SASS content write an empty file
-    fs.writeFile(cssFilePath, '', 'utf8', function(){
-      callback();
-    });
-    return;
-  }
+        sass.on('error', function (err) {
+            logger.info(err.message);
+            if (!isResolved) {
+                isResolved = true;
+                reject(err);
+            }
+        });
 
-  sass.render({
-    data: sassFileContent,
-    includePaths: importPaths,
-    outFile: cssFilePath,
-    outputStyle: 'compressed'
-  }, function (e, output) {
-    if(e) {
-      //Callback with error
-      callback(e);
-    }      
-
-    if(output && output.css){
-      output = output.css;
-    } else {
-      output = '';
-    }
+        // TODO: Consider using close event instead of exit
+        sass.on('exit', function (code, signal) {
+            if (!isResolved) {
+                isResolved = true;
+                if (code === 0) {
+                    resolve();
+                } else {
+                    reject(Error('SASS compiler failed with exit code ' + code));
+                }
+            }
+        });
 
-    fs.writeFile(cssFilePath, output, 'utf8', function(){
-      //File done writing
-      callback();
+        // SASS does not recompile on watch, so directly resolve.        
+        if (options.watch && !isResolved) {
+            isResolved = true;
+            resolve();
+        }
     });
-  });
 }

lib/watch.js

@@ -0,0 +1,5 @@
+var converter = require('./converter');
+
+module.exports = function ($logger, $projectData, $usbLiveSyncService) {
+	return converter.convert($logger, $projectData.projectDir, { watch: true });
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "nativescript-dev-sass",
-  "version": "0.4.2",
+  "version": "0.5.0",
   "description": "SASS CSS pre-processor for NativeScript projects.",
   "scripts": {
     "test": "exit 0",
@@ -18,6 +18,11 @@
         "type": "after-prepare",
         "script": "lib/after-prepare.js",
         "inject": true
+      },
+      {
+        "type": "before-watch",
+        "script": "lib/watch.js",
+        "inject": true
       }
     ]
   },