JavaScript Array Methods & Utility Functions Practice

1531 prep!

Categories Covered:

1. Array Utilities (10 functions)

   • difference(), chunk(), intersection(), unique()
   • flatten(), union(), takeWhile(), dropWhile()
   • partition(), zip()

2. Object Utilities (7 functions)

   • omit(), pick(), merge(), groupBy()
   • invert(), mapValues(), mapKeys()

3. String Utilities (8 functions)

   • capitalizeWords(), camelCase(), snakeCase(), kebabCase()
   • truncate(), charCount(), isPalindrome(), reverseWords()

4. Number Utilities (4 functions)

   • range(), clamp(), sum(), average()

5. Advanced Utilities (6 functions)

   • debounce(), throttle(), memoize()
   • pipe(), compose(), curry()

🚀 How to Use

Git clone

Git clone repo

Practice Individual Exercises

Work through the leveled exercises in order:

1. beginner/ - Start here if new to array methods
2. intermediate/ - Once comfortable with basics
3. medium-hard/ - More complex operations
4. hard/ - Harder
5. expert/ - Even harder
6. bonus/ - Harder

📝 Exercise Guidelines

Before You Start:

• ✅ Read the function description carefully
• ✅ Look at the examples
• ✅ Think about which array/string/object methods to use
• ✅ Consider edge cases

While Working:

• ✅ Try to use native JavaScript methods (map, filter, reduce, etc.)
• ✅ Aim for clean, readable code
• ✅ Consider performance for large inputs
• ✅ Test with different inputs

If Stuck:

1. Break the problem into smaller steps
2. Console.log intermediate values
3. Look up MDN documentation for array methods
4. Try a simpler approach first
5. Check solutions only after genuine attempt

💡 Tips for Success

1. Master reduce() - It's the most powerful array method

   • Can implement map, filter, and most other operations
   • Great for building objects from arrays

2. Understand Method Chaining

   • Many array methods return new arrays
   • Chain operations: arr.filter().map().reduce()

3. Know Your Methods

   • Mutating: push, pop, shift, unshift, splice, sort, reverse
   • Non-mutating: map, filter, reduce, slice, concat

4. Think Functionally

   • Break complex problems into smaller transformations
   • Each method should do one thing well
   • Compose simple operations into complex ones

5. Practice Regularly

   • Start with 2-3 exercises per day
   • Revisit challenging ones
   • Try implementing solutions in multiple ways

📚 Key Array Methods Reference

Iteration

• forEach() - Execute function for each element
• map() - Transform each element
• filter() - Keep elements that pass test
• reduce() - Accumulate to single value
• find() - Find first match
• some() - Test if any pass
• every() - Test if all pass

Manipulation

• push(), pop() - Add/remove from end
• shift(), unshift() - Add/remove from start
• splice() - Add/remove at position
• slice() - Extract portion

Modern ES6+

• flat() - Flatten nested arrays
• flatMap() - Map and flatten
• includes() - Check existence
• from() - Create from iterable

🔗 Helpful Resources

• MDN Array Methods
• MDN Object Methods
• JavaScript.info
• Eloquent JavaScript

📈 Progress Tracking

Track your progress:

• Completed all beginner exercises (8)
• Completed all intermediate exercises (8)
• Completed all medium-hard exercises (7)
• Completed all hard exercises (10)
• Completed all expert exercises (12)
• Completed bonus challenges
• Implemented all 40+ utility functions
• Can explain solutions clearly

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