Pre Requisite for this blog

• Basic JS Understanding honi chahiye bhai

• Promises aane chahiye aapko.

• Promises ke status pata hone chahiye.

What we'll study?

So, aaj hamlog study karne wale hain Promise ke methods ko yaani

• Promise.all()

• Promise.allSettled()

• Promise.any()

• Promise.race()

Isko ham real world analogy se samajhne wale hain toh sit back relaxed and have a chai.

CID Ka Case

Toh ji aaj ham log ko mila hai ek case jise ham sab solve karenge. Usmien hame ek bande Ramu par shak hai

Ham apne shak ko pakka karne ke liye 3 evidence bhejenge (Promise) Doctor salunkhe ke paas (zyadatar API) aur woh hame report wapis denge (Status & Data)

const fingerPrints = new Promise((resolve) => {
  setTimeout(() => resolve("finger print match hogya sir ji"), 2000);
});

const sketch = new Promise((resolve) => {
  setTimeout(() => resolve("Sketch ban gya apradhi ka"), 1000);
});

const footageCheck = new Promise((resolve) => {
  setTimeout(() => resolve("Ye pakda gya aur mat laga mask"), 1500);
});

1. Promise.all() - Sari reports match kare toh hamla

Is approach mien CID wale doctor salunkhe ke sare reports ke aane ka wait karenge

Promise.all([fingerPrints, sketch, footageCheck])
  .then((reports) => {
    console.log(`Salunkhe: ACP ji sari reports aagyi ${reports}`);
    console.log("ACP: Daya darwaja tod do");
  })
  .catch((error) => {
    console.log(`Salunkhe: Are yaar ramu apradhi nhi hai ${error}`);
  });

Bhai ye kya ho raha bhai:

• Sab ka wait karenge (equality on top :)).

• Agar ek ka status rejected toh fail

Problem:

• Ek hi banda sab mien error daal sakta hai so agar aap ise use kar rahe ho toh Best of Luck... 💀

Matalb agar galti se bhi ye hua toh:

const fingerPrints = new Promise((resolve, reject) => {
  setTimeout(() => reject("Match nhi hua"), 1000);
});

Toh fir game over... 💀

2. Promise.allSettled() - Sabki report aane do

ACP ji bolte hain ki daya darwaja todne ke pehle sab ke liye ruk jao

Daya be like: "OK sir"

Promise.allSettled([fingerPrints, sketch, footageCheck])
  .then((results) => {
    console.log(results);
  });

Ismien output sabka aata hai:

[
 { status: "rejected", reason: "Salunkhe: match nhi hua toh kya karu?" },
 { status: "fulfilled", value: "Salunkhe: Ha mukhda toh same hai" },
 { status: "fulfilled", value: "Salunkhe: Pakda gaya chalu ban raha tha" }
]
// array return hoti hai isliye array hai mittar

3. Promise.race() - Joh first woh first

ACP chacha bolte hain ki ek saboot mil jaye isko toh aesa pakdunga ki zindagi bhar nhi bhoolega 😈

Promise.race([fingerPrints, sketch, footageCheck])
  .then((first) => {
    console.log("First Report:", fastest);
  });

Lekin isko use karte hue cautious raho becuase fastest request reject bhi ho sakti hai... Best of Luck 💀

Agar Fulfill hui:

Aur agar Reject hua toh:

4. Promise.any() - Ek Report mili aur fielding set

Promise.any([fingerPrints, sketch, footageCheck])
  .then((result) => {
    console.log("Ek sabut mil gaya", result);
  })
  .catch(() => {
    console.log("Salunkhe ne rishwat li hai ek bhi saboot nhi mila");
  });

Yaha pe aap bas koi ek promise ke fulfill hone ka wait karte ho

Jese hi ek report aayi turant fielding set

sirf ek case hai jismien fail ho jaye joki hai ki sare promise fail ho jaye

Conclusion

• Promise.all() - Ismien sare promise ke resolve hone ka wait karte hain agar koi ek bhi reject hua toh error.

• Promise.allSettled() - Ismien bas sabke settle hone ka wait hota hai resolve ya reject se farak nhi padta.

• Promise.race() - Joh fastest hoga wahi leke chalenge chahe Fulfill ho ya Reject.

• Promise.any() - Bas ek fulfill hone ka wait fir toh fielding set kardenge.

Hope it helped you understand the topic clearly :)