js translation -- performance improvment

CONTRIBUTING.md

@@ -331,6 +331,8 @@ key is to instrument the strings that need translation using
 a module, all you have to do is to `_("Wrap your strings")` using the
 underscore `_` "function".
 
+We use `import {t, tn, TCT} from locales;` in js, JSX file, locales is in `./superset/assets/javascripts/` directory.
+
 To enable changing language in your environment, you can simply add the
 `LANGUAGES` parameter to your `superset_config.py`. Having more than one
 options here will add a language selection dropdown on the right side of the
@@ -342,6 +344,10 @@ navigation bar.
         'zh': {'flag': 'cn', 'name': 'Chinese'},
     }
 
+We need to extract the string to be translated, run the following command:
+
+    pybabel extract -F ./babel/babel.cfg -k _ -k __ -k t -k tn -k tct -o ./babel/messages.pot .
+
 As per the [Flask AppBuilder documentation] about translation, to create a
 new language dictionary, run the following command:
 
@@ -358,6 +364,14 @@ to take effect, they need to be compiled using this command:
 
     fabmanager babel-compile --target superset/translations/
 
+In the case of JS translation, we need to convert the PO file into a JSON file, and we need the global download of the npm package po2json.
+We need to be compiled using this command:
+
+    npm install po2json -g
+
+Execute this command to convert the en PO file into a json file:
+
+    po2json -d superset -f jed1.x superset/translations/en/LC_MESSAGES/messages.po superset/translations/en/LC_MESSAGES/messages.json
 
 ## Adding new datasources
 

babel/babel.cfg

@@ -1,4 +1,8 @@
 [ignore: superset/assets/node_modules/**]
 [python: superset/**.py]
 [jinja2: superset/**/templates/**.html]
+[javascript: superset/assets/javascripts/**.js]
+[javascript: superset/assets/javascripts/**.jsx]
+[javascript: superset/assets/visualizations/**.js]
+[javascript: superset/assets/visualizations/**.jsx]
 encoding = utf-8