<pre class="shiki github-dark shaku"><code>/** * @param {any} data * @return {string} */const PRIMITIVE_TYPES = ['number', 'boolean'];function stringify(data) { const cache = new Set(); function helper(data, cache) { if(cache.has(data)) throw new Error('circulare reference found!'); cache.add(data); // add reference to cache const type = typeof data; if(type === 'bigint') throw new Error('cannot stringify bigint'); if(type === 'number' &amp;&amp; (Number.isNaN(data) || data === Infinity || data === -Infinity)) return "null"; if(data == null) return "null"; if(type === 'string') return `"${data}"`; if(PRIMITIVE_TYPES.includes(type)) return `${data}`; // array if(Array.isArray(data)) { const res = []; data.forEach(ele =&gt; { if(typeof ele === 'symbol') res.push("null"); else res.push(stringify(ele)) }); return `[${res}]`; } // object if(type === 'object') { if(data instanceof Date) return `"${data.toISOString()}"`; const res = []; Object.entries(data).forEach(([key, value]) =&gt; { if(value !== undefined) res.push(`${stringify(key)}:${stringify(value)}`); }); return `{${res}}` } cache.delete(data); // remove reference from cache return undefined; } return helper(data, cache);}</code></pre>

With circular reference

I believe you've used JSON.stringify() before, do you know the details of how it handles arbitrary data? Please have a guess on the details and then t…