Add source maps support for Babel

Author: Andrey Fedoseev

CHANGES.rst

@@ -9,6 +9,7 @@ Dev
 - Add source maps support for LESS
 - Add source maps support for CoffeeScript
 - Add source maps support for Stylus
+- Add source maps support for Babel
 
 
 1.0.1

README.rst

@@ -190,13 +190,16 @@ Babel
 ``executable``
   Path to Babel compiler executable. Default: ``"babel"``.
 
+``sourcemap_enabled``
+  Boolean. Set to ``True`` to enable source maps. Default: ``False``
+
 ``modules``
   Babel `modules <https://babeljs.io/docs/usage/modules/>`_ command line option. Default: ``None`` (uses Babel's default option).
 
 Example::
 
     STATIC_PRECOMPILER_COMPILERS = (
-        ('static_precompiler.compilers.Babel', {"executable": "/usr/bin/babel", "modules": "amd"}),
+        ('static_precompiler.compilers.Babel', {"executable": "/usr/bin/babel", "sourcemap_enabled": True, "modules": "amd"}),
     )
 
 

static_precompiler/compilers/babel.py

@@ -1,4 +1,6 @@
+import json
 import os
+import posixpath
 
 from static_precompiler import exceptions, utils
 
@@ -15,16 +17,20 @@ class Babel(base.BaseCompiler):
     input_extension = "es6"
     output_extension = "js"
 
-    def __init__(self, executable="babel", modules=None):
+    def __init__(self, executable="babel", sourcemap_enabled=False, modules=None):
         self.executable = executable
+        self.is_sourcemap_enabled = sourcemap_enabled
         self.modules = modules
         super(Babel, self).__init__()
 
     def compile_file(self, source_path):
         args = [
-            self.executable
+            self.executable,
         ]
 
+        if self.is_sourcemap_enabled:
+            args.append("-s")
+
         if self.modules is not None:
             args.extend(["--modules", self.modules])
 
@@ -41,6 +47,21 @@ def compile_file(self, source_path):
         if errors:
             raise exceptions.StaticCompilationError(errors)
 
+        if self.is_sourcemap_enabled:
+            sourcemap_full_path = full_output_path + ".map"
+
+            with open(sourcemap_full_path) as sourcemap_file:
+                sourcemap = json.loads(sourcemap_file.read())
+
+            # Babel can't add correct relative paths in source map when the compiled file
+            # is not in the same dir as the source file. We fix it here.
+            sourcemap["sourceRoot"] = "../" * len(source_path.split("/")) + posixpath.dirname(source_path)
+            sourcemap["sources"] = [os.path.basename(source) for source in sourcemap["sources"]]
+            sourcemap["file"] = posixpath.basename(os.path.basename(full_output_path))
+
+            with open(sourcemap_full_path, "w") as sourcemap_file:
+                sourcemap_file.write(json.dumps(sourcemap))
+
         return self.get_output_path(source_path)
 
     def compile_source(self, source):

static_precompiler/tests/test_babel.py

@@ -26,6 +26,21 @@ def test_compile_file(monkeypatch, tmpdir):
 """
 
 
+def test_sourcemap(monkeypatch, tmpdir):
+
+    monkeypatch.setattr("static_precompiler.settings.ROOT", tmpdir.strpath)
+
+    compiler = compilers.Babel(sourcemap_enabled=False)
+    compiler.compile_file("scripts/test.es6")
+    full_output_path = compiler.get_full_output_path("scripts/test.es6")
+    assert not os.path.exists(full_output_path + ".map")
+
+    compiler = compilers.Babel(sourcemap_enabled=True)
+    compiler.compile_file("scripts/test.es6")
+    full_output_path = compiler.get_full_output_path("scripts/test.es6")
+    assert os.path.exists(full_output_path + ".map")
+
+
 def test_compile_source():
     compiler = compilers.Babel()