JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://signel.onrender.com/signel.js"></script>
<div id="app">
<div id="my-tree">
<b id="tree-btn">My tree $$btn</b>
</div>
</div>
JavaScript
let myTree = state({ btn: '[+]'})
dom('#tree-btn').bind(myTree)
dom('#tree-btn').css('cursor:pointer').click(()=> myTree.btn = myTree.btn === '[+]' ? '[-]' : '[+]')