Add source map output support to the CLI

lib/precompiler.js

@@ -2,6 +2,9 @@
 var fs = require('fs'),
     Handlebars = require('./index'),
     basename = require('path').basename,
+    SourceMap = require('source-map'),
+      SourceMapConsumer = SourceMap.SourceMapConsumer,
+      SourceNode = SourceMap.SourceNode,
     uglify = require('uglify-js');
 
 module.exports.cli = function(opts) {
@@ -45,20 +48,23 @@ module.exports.cli = function(opts) {
   var extension = opts.extension.replace(/[\\^$*+?.():=!|{}\-\[\]]/g, function(arg) { return '\\' + arg; });
   extension = new RegExp('\\.' + extension + '$');
 
-  var output = [];
+  var output = new SourceNode();
   if (!opts.simple) {
     if (opts.amd) {
-      output.push('define([\'' + opts.handlebarPath + 'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];');
+      output.add('define([\'' + opts.handlebarPath + 'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];');
     } else if (opts.commonjs) {
-      output.push('var Handlebars = require("' + opts.commonjs + '");');
+      output.add('var Handlebars = require("' + opts.commonjs + '");');
     } else {
-      output.push('(function() {\n');
+      output.add('(function() {\n');
     }
-    output.push('  var template = Handlebars.template, templates = ');
-    output.push(opts.namespace);
-    output.push(' = ');
-    output.push(opts.namespace);
-    output.push(' || {};\n');
+    output.add('  var template = Handlebars.template, templates = ');
+    if (opts.namespace) {
+      output.add(opts.namespace);
+      output.add(' = ');
+      output.add(opts.namespace);
+      output.add(' || ');
+    }
+    output.add('{};\n');
   }
   function processTemplate(template, root) {
     var path = template,
@@ -83,6 +89,9 @@ module.exports.cli = function(opts) {
         knownHelpersOnly: opts.o
       };
 
+      if (opts.map) {
+        options.srcName = path;
+      }
       if (opts.data) {
         options.data = true;
       }
@@ -95,18 +104,26 @@ module.exports.cli = function(opts) {
       }
       template = template.replace(extension, '');
 
+      var precompiled = Handlebars.precompile(data, options);
+
+      // If we are generating a source map, we have to reconstruct the SourceNode object
+      if (opts.map) {
+        var consumer = new SourceMapConsumer(precompiled.map);
+        precompiled = SourceNode.fromStringWithSourceMap(precompiled.code, consumer);
+      }
+
       if (opts.simple) {
-        output.push(Handlebars.precompile(data, options) + '\n');
+        output.add([precompiled, '\n']);
       } else if (opts.partial) {
         if(opts.amd && (opts.templates.length == 1 && !fs.statSync(opts.templates[0]).isDirectory())) {
-          output.push('return ');
+          output.add('return ');
         }
-        output.push('Handlebars.partials[\'' + template + '\'] = template(' + Handlebars.precompile(data, options) + ');\n');
+        output.add(['Handlebars.partials[\'', template, '\'] = template(', precompiled, ');\n']);
       } else {
         if(opts.amd && (opts.templates.length == 1 && !fs.statSync(opts.templates[0]).isDirectory())) {
-          output.push('return ');
+          output.add('return ');
         }
-        output.push('templates[\'' + template + '\'] = template(' + Handlebars.precompile(data, options) + ');\n');
+        output.add(['templates[\'', template, '\'] = template(', precompiled, ');\n']);
       }
     }
   }
@@ -120,22 +137,42 @@ module.exports.cli = function(opts) {
     if (opts.amd) {
       if(opts.templates.length > 1 || (opts.templates.length == 1 && fs.statSync(opts.templates[0]).isDirectory())) {
         if(opts.partial){
-          output.push('return Handlebars.partials;\n');
+          output.add('return Handlebars.partials;\n');
         } else {
-          output.push('return templates;\n');
+          output.add('return templates;\n');
         }
       }
-      output.push('});');
+      output.add('});');
     } else if (!opts.commonjs) {
-      output.push('})();');
+      output.add('})();');
     }
   }
-  output = output.join('');
+
+
+  if (opts.map) {
+    output.add('\n//# sourceMappingURL=' + opts.map + '\n');
+  }
+
+  output = output.toStringWithSourceMap();
+  output.map = output.map + '';
 
   if (opts.min) {
-    output = uglify.minify(output, {fromString: true}).code;
+    output = uglify.minify(output.code, {
+      fromString: true,
+
+      outSourceMap: opts.map,
+      inSourceMap: JSON.parse(output.map)
+    });
+    if (opts.map) {
+      output.code += '\n//# sourceMappingURL=' + opts.map + '\n';
+    }
   }
 
+  if (opts.map) {
+    fs.writeFileSync(opts.map, output.map, 'utf8');
+  }
+  output = output.code;
+
   if (opts.output) {
     fs.writeFileSync(opts.output, output, 'utf8');
   } else {