What are JavaScript PROMISES? 🤞
2023 ж. 20 Жел.
31 774 Рет қаралды
#JavaScript #tutorial #courses
// Promise = An Object that manages asynchronous operations.
// Wrap a Promise Object around {asynchronous code}
// "I promise to return a value"
// DO THESE CHORES IN ORDER
// 1. WALK THE DOG
// 2. CLEAN THE KITCHEN
// 3. TAKE OUT THE TRASH
// Promise = An Object that manages asynchronous operations. // Wrap a Promise Object around {asynchronous code} // "I promise to return a value" // PENDING -> RESOLVED or REJECTED // new Promise((resolve, reject) => {asynchronous code}) // DO THESE CHORES IN ORDER // 1. WALK THE DOG // 2. CLEAN THE KITCHEN // 3. TAKE OUT THE TRASH function walkDog(){ return new Promise((resolve, reject) => { setTimeout(() => { const dogWalked = false; if(dogWalked){ resolve("You walk the dog 🐕"); } else{ reject("You DIDN'T walk the dog"); } }, 1500); }); } function cleanKitchen(){ return new Promise((resolve, reject) => { setTimeout(() => { const kitchenCleaned = true; if(kitchenCleaned){ resolve("You clean the kitchen 🧹"); } else{ reject("You DIDN'T clean the kitchen"); } }, 2500); }); } function takeOutTrash(){ return new Promise((resolve, reject) => { setTimeout(() => { const trashTakenOut = true; if(trashTakenOut){ resolve("You take out the trash ♻"); } else{ reject("You DIDN'T take out the trash"); } }, 500); }); } walkDog().then(value => {console.log(value); return cleanKitchen()}) .then(value => {console.log(value); return takeOutTrash()}) .then(value => {console.log(value); console.log("You finished all the chores!")}) .catch(error => console.error(error));
Finally, I understand PROMISES. Thanks
Take out the trash "is really quick" => open the window/door - throw the trash - close. 🙊 .... Thank you! Getting closer to understand. (The value in the end is a bit "confusing", but I will make some studies and samples.)
async/await simplifies the process in the next topic
This is super helpful, last night was having trouble wrapping my head around this but this video really made it click! Thanks man!
It is the best explanation ever. Thanks
Your video made promises clear in my head. Thank you for your effort.
Bro, you rock. Thanks for the video!
The best tutorial on promises. Thanks mannn
I finally fully understood. Thanks man.
Thank you, it was very clear and simple.
Very good thank you.
THE BEST EXPLANATION
You are great!!!! Thanks a lot
Youre a savior man!
The way of your explain is Awesome #BroCodez Thank You
Can you please explain the code you wrote inside the then() method. What does it do and why are we creating the arrow function with value parameter and how is it able to access the resolve value
i just searched about this tomorrow and you uploaded it today what are the odds ;)
Thank you, it really helped me
really helpful. Thanks
The best!
You are awesome
Thank you very much
Can you not method chain instead of returning the values of the promises?
I noticed some tutorials will create a variable equally a new promise kinda like this "var p = new Promise((resolve, reject))" ... in your example you returned promises, is there a preferred way or this situational ?
Honestly I find the "pyramid of doom" less confusing than promises
😂😂😂😂 same
😅 It gets easier with a lot of repetition… It was hard to wrap my head around but just going back over and over and coding along simultaneously can & will do the trick.
I understood it, but you made it a little unclear than it should have. Using .then.then.then without returning anything would've been a little clearer maybe, but there are a few other ways.
If the code is asynchronous why does the first reject prevent the other functions from being executed
where was this when i was banging my head against the wall learning this ;.;
I was probably still recording it lol
how he do this 1:50 ? This little picture ?
window key + > , for mac is CTRL + CMD + Space
@@hongquannguyen5532 Thank you, very appreciate !
thanks bud