Straight promise solution, though fails the config keys order test case, need to define a hash for that, but other than that solution works, we don't keep a key for more that 1000ms in the cache
<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) { let cache = {}; // identical api calls return same result for 10000ms return function(path, config) { function clearCache() { cache = {}; } // create unique key for the cache // need to define a proper hash // so fails the "order of keys is irrevelent in config" test case let key = `${path}${JSON.stringify(config)}`; let out = new Promise((resolve, reject) =&gt; { if (key in cache) { resolve(cache[key]); } else { getAPI(path, config).then((val) =&gt; { cache[key] = val; resolve(val); }).catch((err) =&gt; { reject(err); }) } }) cache[key] = out setTimeout(() =&gt; { delete cache[key]; }, 1000) return out; }}</code></pre>

PROMISE AND CACHE - STRAIGHT FORWARD SOLUTION (BUT NO HASH)

> ⚠️ 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(…