🤞 Promises Explained Like You're 5
Building AI systems and writing about how they actually work. Master of AI @ University of Technology Sydney. Previously B.Tech CS with focus on IoT. I believe the best way to learn is to explain. That's why I'm documenting tech concepts with simple analogies (@sreekarreddy.com). AWS Certified • Azure AI Certified • Neo4j Professional • Google Data Analytics When not coding: exploring Sydney, working on side projects, and teaching tech to anyone who'll listen.
I promise to call you when I'm done
Day 52 of 149
👉 Full deep-dive with code examples
The Pizza Order
You order pizza for delivery.
The restaurant gives you a promise:
- "Your pizza will arrive" (pending)
- Eventually: "Pizza's here!" (fulfilled) 🍕
- Or: "Sorry, we're out of dough" (rejected) ❌
JavaScript promises work the same way!
The Problem with Callbacks
Remember callback hell?
doA(function () {
doB(function () {
doC(function () {
// 🌀 Spiral of doom
});
});
});
Promises to the Rescue
doA()
.then(() => doB())
.then(() => doC())
.then(() => done!)
.catch((error) => handleError);
Flat! Readable! Error handling in one place!
Three States
| State | Meaning |
| Pending | Still working on it |
| Fulfilled | Success! Here's the result |
| Rejected | Failed! Here's the error |
Creating a Promise
const myPromise = new Promise((resolve, reject) => {
if (success) {
resolve("Here's your data!");
} else {
reject("Something went wrong!");
}
});
In One Sentence
Promises represent a future value that will eventually be available, making async code cleaner than callbacks.
🔗 Enjoying these? Follow for daily ELI5 explanations!
Making complex tech concepts simple, one day at a time.