wgMessageWallsExist extends the mw.config variable to add a new wgVariable called wgMessageWallsExist. This method, unlike the others, does not return a usable value but instead returns a promise which you can use to separate logic for message walls and talk pages.
Usage
To use do as follows:
mw.hook('dev.enablewallext').add(function(wgMessageWallsExist) {
wgMessageWallsExist.then(
function () {
// Message walls do exist on this wiki
},
function () {
// Message walls do not exist on this wiki
}
);
});
importArticle({
type: 'script',
article: 'u:dev:MediaWiki:WgMessageWallsExist.js'
});
Text above can be found here (edit)