write scss BEM style in template
const sid = require('sind');
const tpl = `
<div class="header other-class">
<div class="&-menu">
<div class="&__item">1</div>
<div class="&__item">2</div>
<div class="&__item">3</div>
<div class="&__item">4</div>
</div>
</div>
`;
sid(tpl)
turns to
"<div class=\"header other-class\">\n <div class=\"header-menu\">\n <div class=\"header-menu__item\">1</div>\n <div class=\"header-menu__item\">2</div>\n <div class=\"header-menu__item\">3</div>\n <div class=\"header-menu__item\">4</div>\n </div>\n</div>";
more complex case
<div class="leaflet&-header other-class">
<div class="@at-root&-menu">
<div class="&__item">1</div>
<div class="&__item">2</div>
<div class="&__item">3</div>
<div class="&__item">4</div>
</div>
</div>
sind was inspired by scss-dom