Extracting Javascript gettext messages using Babel CLI extractor

Question

It is stated here that Babel can extract gettext messages for Python and Javascript files.

Babel comes with a few builtin extractors: python (which extracts messages from Python source files), javascript, and ignore (which extracts nothing).

The command line extractor is documented here - but with no examples on usage.

Also in the same pointer above, there is some mention of a config file to be used with extraction, but not much expanded on.

When I run the basic command for the extractor on a dir with js files, I get only the .PO header generated but no messages.

$ pybabel extract   /path/to/js-dir

# Translations template for PROJECT.
# Copyright (C) 2012 ORGANIZATION
# This file is distributed under the same license as the PROJECT project.
# FIRST AUTHOR <EMAIL@ADDRESS>, 2012.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: PROJECT VERSION\n"
"Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
"POT-Creation-Date: 2012-04-22 19:39+1000\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=utf-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Generated-By: Babel 0.9.6\n"

$ 

Here is a sample segment from a js file I'm trying to extract messages for:

else if(data.status == "1"){
    var follow_html = gettext('Follow');
    object.attr("class", 'button follow');
    object.html(follow_html);
    var fav = getFavoriteNumber();
    fav.removeClass("my-favorite-number");
    if(data.count === 0){
        data.count = '';
        fav.text('');
    }else{
        var fmts = ngettext('%s follower', '%s followers', data.count);
        fav.text(interpolate(fmts, [data.count]));
    }
}

I would appreciate it if someone can provide exact CLI options and config settings to make the extraction work, or a pointer to such.

Answer 1

Create a file (babel.cfg) with the following content:

[javascript:*.js]
encoding = utf-8

Then, do:

pybabel extract -F babel.cfg /path/to/js-dir

That should be enough for you to have some message strings.

BTW, you can consult the help for the extract command by doing:

pybabel extract --help

Answer 2

I had a similar issue and was able to get around it by disabling default keywords with babel.

pybabel extract -k __ -F babel.cfg --no-default-keywords /path/to/js-dir 

You must specify at least one keyword in the command when you disable the defaults (-k [keyword]). I chose -k __ because "__" was a pattern I was looking for.

Just use this command and replace the "__" after -k with one from your babel.cfg file.

Edit: this allows you to use your own keywords rather than gettext()

Answer 3

You can create an object in as flask global and translate it with gettext

g.i18n = {
    'Casa' : lazy_gettext('Home'),
    'Auto' : lazy_gettext('Car'),
    'Persona' : lazy_gettext('Person')
}

Then add it as a variable

<script>
    var i18n = {{ g.i18n | tojson }}
</script>

and use it in JS:

var labelTranslate = {
                    Casa: i18n.Casa,
                    Persona: i18n.Persona,
                    Auto: i18n.Auto
                };

Answer 4

You can actually use gettext directly in Javascript.

See: jsgettext. It allows you to use the standard *gettext functions, including the one using contexts and/or plural forms.

It can read PO/MO files or you can import custom made JSON files instead.

See this file of this project for a complete example.