Get first commit of private repo

first-commit.js

// extended from https://github.com/FarhadG/init
(b=>fetch(new Request('https://api.github.com/repos/'+b[1]+'/commits?sha='+(b[2]||''),{
  headers: new Headers({Authorization:'token ...'}),
}))
  .then(c=>Promise.all([c.headers.get('link'),c.json()]))
  .then(c=>{
    if(c[0]){
      var d=c[0].split(',')[1].split(';')[0].slice(2,-1);
      return fetch(new Request(d,{
        headers: new Headers({Authorization:'token ...'}),
      })).then(e=>e.json());
    }
    return c[1];
  })
  .then(c=>c.pop().html_url)
  .then(c=>window.location=c)
)(window.location.pathname.match(/\/([^\/]+\/[^\/]+)(?:\/tree\/([^\/]+))?/));