wikimedia/mediawiki-extensions-MobileFrontend

/**
 * Store the user's preferred editor
 *
 * @param {string} editor 'VisualEditor' or 'SourceEditor'
 */
module.exports = function setPreferredEditor( editor ) {
    if ( mw.user.isNamed() ) {
        new mw.Api().saveOption( 'mobile-editor', editor ).then( function () {
            mw.user.options.set( 'mobile-editor', editor );
        } );
    } else {
        mw.storage.set( 'preferredEditor', editor );
    }
};