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Shahzaib ur Rehman
Shahzaib ur Rehman

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My Favorite 10 JavaScript One-Liners That Save Time Daily

#webdev #javascript #programming #tutorial

🧠 Introduction

As developers, we’re constantly looking for ways to write cleaner, shorter, and more efficient code. Over time, I’ve picked up some powerful JavaScript one-liners that help me speed up development, simplify logic, and even impress teammates during code reviews.

In this post, I’ll share my 10 favorite JavaScript one-liners I use regularly — with real examples and tips for when to use them.

🔟 1. Remove Duplicates from an Array 

const unique = [...new Set([1, 2, 2, 3, 4, 4])]; 
// [1, 2, 3, 4]
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✅ Great for cleaning up data or ensuring unique values in a form or filter.

9️⃣ 2. Swap Two Variables 

[a, b] = [b, a];
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✅ Simple and clean — no temp variable needed.

8️⃣ 3. Short-Circuit Default Values 

const name = user.name || "Guest";
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✅ A quick fallback if a value is undefined or falsy.

7️⃣ 4. Check if a Number is Even 

const isEven = num => num % 2 === 0;
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✅ Works great inside conditionals, filters, or validators.

6️⃣ 5. Flatten an Array 

const flat = arr.flat(Infinity);
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✅ Removes all levels of nesting in one go.

5️⃣ 6. Generate a Random Hex Color 

const color = '#' + Math.floor(Math.random()*16777215).toString(16);
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✅ Perfect for random themes, gradients, or creative UIs.

4️⃣ 7. Count Occurrences in an Array 

const count = arr.reduce((a, v) => (a[v] = (a[v] || 0) + 1, a), {});
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✅ Handy for analytics, tagging systems, or filtering results.

3️⃣ 8. Get the Last Item of an Array 

const last = arr.at(-1);
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✅ Cleaner than arr[arr.length - 1].

2️⃣ 9. Capitalize the First Letter 

const cap = str => str.charAt(0).toUpperCase() + str.slice(1);
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✅ Great for formatting names, titles, or headings.

1️⃣ 10. Delay with Promises 

const wait = ms => new Promise(res => setTimeout(res, ms));
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✅ Useful for delays in async flows, animations, or retries.

📌 Final Thoughts

These one-liners aren’t just clever tricks — they’re practical tools I use in real projects.
By mastering these patterns, you’ll not only write less code, but also improve your ability to think functionally and write expressively in JavaScript.

🚀 Try using 2–3 of these in your next project and feel the difference!

💬 Got your own favorite one-liner? Drop it in the comments and let’s build the ultimate list!
🔁 Save this post for future quick wins in your daily coding!

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