MediaWiki:Common.js

mw.loader.using( 'mediawiki.util', function () {
    const groups = mw.config.get( 'wgUserGroups' );

    const isPrivileged =
        groups.includes( 'editor' ) ||
        groups.includes( 'approver' ) ||
        groups.includes( 'sysop' );

    if ( !isPrivileged ) {
        mw.util.addCSS(
            `
            #ca-edit,
            #ca-edit-source,
            #ca-ve-edit,
            #ca-viewsource {
                display: none !important;
            }
            `
        );
    }
});