Hands-On Data Structures and Algorithms with JavaScript

Avoiding pyramid of doom

Pyramid of doom is a classic scenario where we have tons of nesting or branching. This makes the code overly complex and the unit testing a very complex job:

promise1()    .then((resp) => {        promise2(resp)            .then((resp2) => {                promise3(resp2)                    .then((resp3) => {                        if(resp3.something) {                            // do something                        } else {                            // do something else                        }                    });            });    });

Instead, do the following:

promise1()    .then((resp) => {        return promise2(resp);    })   .then((resp2) => {        return promise3(resp2);    })                    .then((resp3) => {        if(resp3.something) {            // do something        } else {            // do something else        }    })