<pre class="shiki github-dark shaku"><code>const nodeId = Symbol('nodeId');let idGen = 0;class NodeStore { constructor() { // { "id_ast1": value, "id_sxx2": value, ... } this.store = {}; } /** * @param {Node} node * @param {any} value */ set(node, value) { const id = node[nodeId] || idGen + 1; node[nodeId] = id; this.store[id] = value; } /** * @param {Node} node * @return {any} */ get(node) { return this.store[node[nodeId]]; } /** * @param {Node} node * @return {Boolean} */ has(node) { const id = node[nodeId]; return this.store.hasOwnProperty(id); }}</code></pre>

This is my accepted solution