<pre class="shiki github-dark shaku"><code>/** * @param {(path: string, config: any) =&gt; Promise&lt;any&gt;} getAPI * @returns {(path: string, config: any) =&gt; Promise&lt;any&gt; &amp; {clearCache: () =&gt; void}} */function createGetAPIWithMerging(getAPI) { const cache = new Map(); this.clearCache = () =&gt; { cache.clear(); } return (path, config) =&gt; { const sortedConfig = Object.keys(config).sort().reduce((res, key) =&gt; { return {...res, [key]: config[key]}; }, {}); const cacheKey = JSON.stringify({path, config: sortedConfig}); if (cache.has(cacheKey)) { return cache.get(cacheKey); } const resp = getAPI(path, config); cache.set(cacheKey, resp); if (cache.size &gt; 5) { cache.delete(cache.keys().next().value); } setTimeout(() =&gt; { cache.delete(cacheKey); }, 1000); return resp; }}</code></pre>

simple solution

> ⚠️ This questions is updated on Oct 22, 2022 which has breaking changes on test specs.Thanks to @Qzlt4LK. Suppose we have a utility function getAPI(…