Break the chain When you need to access the intermediate values in your chain, you should split your chain apart in those single pieces that you need. Instead of attaching one callback and somehow trying to use its parameter multiple times, attach multiple callbacks to the same promise – wherever you need the result value. … Read more
Promises have state, they start as pending and can settle to: fulfilled meaning that the computation completed successfully. rejected meaning that the computation failed. Promise returning functions should never throw, they should return rejections instead. Throwing from a promise returning function will force you to use both a } catch { and a .catch. People … Read more
The deferred antipattern (now explicit-construction anti-pattern) coined by Esailija is a common anti-pattern people who are new to promises make, I’ve made it myself when I first used promises. The problem with the above code is that is fails to utilize the fact that promises chain. Promises can chain with .then and you can return … Read more
var p = promiseReturnedFromAFunction(); var time = new Date().getTime(); var user=”undefined”; p.then(() => { while(user === ‘undefined’ && Math.abs(time – new Date().getTime()) < 10000) { if(somecondition) { user=”user”; break; } } }); I think you have it inverted. You want to wait for the promise to resolve, then loop through your condition checks to make … Read more