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Alex Spinov
Alex Spinov

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9 JavaScript One-Liners That Replace Entire Libraries

#webdev #programming #javascript #beginners

Stop installing packages for things JavaScript can do natively

Every npm package adds weight, dependencies, and potential vulnerabilities. Here are 9 things you might be importing a library for — that you can do in one line.

1. Deep Clone (replaces lodash.cloneDeep) 

const clone = structuredClone(originalObject);
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Built into every modern browser and Node 17+. Handles nested objects, arrays, dates, maps, sets.

2. UUID Generation (replaces uuid) 

const id = crypto.randomUUID();
// '3b241101-e2bb-4d7a-8613-e0c07a8a3c59'
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Built into browsers and Node 19+. No package needed.

3. Debounce (replaces lodash.debounce) 

const debounce = (fn, ms) => { let t; return (...a) => { clearTimeout(t); t = setTimeout(() => fn(...a), ms); }; };
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4. Flatten Array (replaces lodash.flatten) 

const flat = nestedArray.flat(Infinity);
// [1, [2, [3, [4]]]] → [1, 2, 3, 4]
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5. Unique Array (replaces lodash.uniq) 

const unique = [...new Set(array)];
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6. Group By (replaces lodash.groupBy) 

const grouped = Object.groupBy(users, user => user.role);
// { admin: [...], user: [...] }
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Available in Node 21+ and modern browsers.

7. Sleep / Delay (replaces various timer packages) 

const sleep = ms => new Promise(r => setTimeout(r, ms));
await sleep(1000); // Wait 1 second
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8. Query String Parsing (replaces qs) 

const params = Object.fromEntries(new URLSearchParams('name=Alex&role=dev'));
// { name: 'Alex', role: 'dev' }
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9. Date Formatting (replaces moment/dayjs for simple cases) 

new Date().toLocaleDateString('en-US', { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' });
// 'Wednesday, March 26, 2026'
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For complex date math, you still need a library. But for formatting? Intl handles it.

When to still use the library

  • lodash: If you need 10+ utility functions, importing the whole thing is fine
  • date-fns/dayjs: If you're doing date math (add days, diff, timezones)
  • uuid: If you need v1/v5 UUIDs specifically (crypto.randomUUID is v4 only)

But for most projects? These one-liners are enough.

What npm package did you recently realize you didn't need?

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