9.10.1 Traversing with Writer
HTML
<script src="https://rawgit.com/eu81273/jsfiddle-console/master/console.js"></script>
JavaScript
const p1 = new Promise((res) => { setTimeout(res, 101, 5) });
p1.then(x => ({ then: (resolve, reject) => resolve(x + 4) }))
.then(v => console.log("result " + v)) //result 9
.catch(error => console.log("error " + error))