The Flask-Babel tool we are using does not supply any native way to access translations via JavaScript, so would require hacky solutions like adding data attributes or hidden elements to the HTML.
We have several areas of the application where we must use text in JavaScript. The DataTables plugin for example allows you to provide strings to use for the buttons it generates, but they must be defined in JS.
This library seems to be a good solution: https://github.com/guillaumepotier/gettext.js
But another library needed to do string extraction to create .pot files - see https://www.npmjs.com/package/gettext-extractor
IMPORTANT: Extracting strings from JavaScript files separately to the Python and HTML extraction, we end up with a separate .pot file.
This is not ideal as it means that duplicate strings will not be merged. If we do use a separate extractor for JS strings then we need to *merge* the .pot files afterwards. A better solution might be to use the main default [[https://www.gnu.org/software/gettext/ - GNU gettext library]] - see https://www.gnu.org/software/gettext/manual/html_node/xgettext-Invocation.html
This is capable of extracting from Python, HTML and JavaScript (along with all other main languages)
Note: Webpack loader which could be useful: https://github.com/mrblueblue/gettext-loader but unlikely to be needed in our case