Jayakrishna D’s Post

🚀 JavaScript Deep Dive: Promise.all vs Promise.allSettled One of the most common async pitfalls I see in interviews and real-world codebases is misunderstanding how "Promise.all()" behaves compared to "Promise.allSettled()". Let’s break it down 👇 🔹 Promise.all() - Fails fast - If any one promise rejects, the entire result rejects immediately - You lose results of other promises Promise.all([ Promise.resolve('success'), Promise.reject('failure') ]) .catch(console.log); // Output: "failure" 👉 Best used when: - All operations are dependent - You need all results or nothing --- 🔹 Promise.allSettled() - Never fails - Waits for all promises to complete (resolved or rejected) - Returns detailed status of each promise Promise.allSettled([ Promise.resolve('success'), Promise.reject('failure') ]) .then(console.log); /* [ { status: 'fulfilled', value: 'success' }, { status: 'rejected', reason: 'failure' } ] */ 👉 Best used when: - Tasks are independent - You want to analyze both success & failure cases --- 💡 Pro Tip (Interview Insight): If you say: «“Use "Promise.all" for dependent APIs and "allSettled" for resilient UI flows”» 👉 You instantly sound like a senior engineer. --- ⚡ Real-world example: - "Promise.all" → Payment + Order Creation (must both succeed) - "Promise.allSettled" → Fetching dashboard widgets (show partial data if some fail) --- 🔥 Mastering these small differences = writing robust, production-ready async code --- #JavaScript #Frontend #ReactJS #WebDevelopment #AsyncProgramming #CodingInterview #SeniorDeveloper

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