deps: Add option to skip minifying Javascript files.

Plotly.js take around 20 seconds to minify with the Closure
compiler so it is taken out.

Fixes zulip#3076.

tools/minify-js

@@ -105,11 +105,16 @@ for js_group, filespec in six.iteritems(JS_SPECS):
     in_files = [os.path.join(STATIC_PATH, filename)
                 for filename in filespec['source_filenames']]
 
+    min_files = [os.path.join(STATIC_PATH, filename)
+                 for filename in filespec.get('minifed_source_filenames')
+                 or []]
+
     out_file = os.path.join(MIN_DIR, os.path.basename(filespec['output_filename']))
     map_file = os.path.join(MAP_DIR, os.path.basename(filespec['output_filename'])
                             + '.map')
 
-    if (not 'force_minify' in filespec) and (prev_deploy and len(set(in_files) & changed_files) == 0):
+    if (not 'force_minify' in filespec) and \
+       (prev_deploy and len(set(in_files) & changed_files) == 0):
         # Try to reuse the output file from previous deploy
         try:
             for dest in [out_file, map_file]:
@@ -132,4 +137,10 @@ for js_group, filespec in six.iteritems(JS_SPECS):
 
     # Write out the JS
     with open(out_file, 'wb') as fp:
+        # Minified source files (most likely libraries) should be loaded
+        # first to prevent any dependency errors.
+        for file in min_files:
+            with open(file, 'rb') as f:
+                fp.write(f.read())
+
         fp.write(js)

zerver/templatetags/minified_js.py

@@ -19,7 +19,13 @@ def __init__(self, sourcefile):
     def render(self, context):
         # type: (Dict[str, Any]) -> str
         if settings.DEBUG:
-            scripts = settings.JS_SPECS[self.sourcefile]['source_filenames']
+            source_files = settings.JS_SPECS[self.sourcefile]
+            normal_source = source_files['source_filenames']
+            minified_source = source_files.get('minifed_source_filenames')
+
+            # Minified source files (most likely libraries) should be loaded
+            # first to prevent any dependency errors.
+            scripts = minified_source + normal_source if minified_source else normal_source
         else:
             scripts = [settings.JS_SPECS[self.sourcefile]['output_filename']]
         script_urls = [staticfiles_storage.url(script) for script in scripts]

zproject/settings.py

@@ -858,10 +858,12 @@ def get_secret(key):
     },
     'stats': {
         'source_filenames': (
-            'node_modules/plotly.js/dist/plotly.js',
             'node_modules/jquery/dist/jquery.js',
             'js/portico/stats.js'
         ),
+        'minifed_source_filenames': (
+            'node_modules/plotly.js/dist/plotly.min.js',
+        ),
         'output_filename': 'min/stats.js'
     },
     # We also want to minify sockjs separately for the sockjs iframe transport