For lazy people, like me, a snippet based on Nikhil's solution
<input id=username type="text" placeholder="github username or repo link">_x000D_
<button onclick="fetch(`https://api.github.com/users/${username.value.replace(/^.*com[/]([^/]*).*$/,'$1')}/events/public`).then(e=> e.json()).then(e => [...new Set([].concat.apply([],e.filter(x => x.type==='PushEvent').map(x => x.payload.commits.map(c => c.author.email)))).values()]).then(x => results.innerText = x)">GO</button>_x000D_
<div id=results></div>
_x000D_