<pre class="shiki github-dark shaku"><code>function undefinedToNull(arg) { if(arg === undefined || arg === null) return null; for (key in arg) { if(typeof arg[key] === 'object') arg[key] = undefinedToNull(arg[key]); else if(arg[key] === undefined) { arg[key] = null; } } return arg}</code></pre>

This is my Solution !

One of the differences between null and undefined is how they are treated differently in JSON.stringify(). JSON.stringify({a: null}) // '{"a":null}'JS…