JavaScript Programming Methods

A comprehensive collection of JavaScript programming methods with detailed explanations, practical examples, and best practices.

📁 Project Structure

javascript-programming-methods/
├── array-methods/
│   ├── filter.js              - Filter array elements by condition
│   ├── find.js                - Find elements (find, findIndex, findLast)
│   ├── flat-flatMap.js        - Flatten nested arrays
│   ├── forEach.js             - Iterate over array elements
│   ├── includes-indexOf.js    - Search methods (includes, indexOf, lastIndexOf)
│   ├── map.js                 - Transform array elements
│   ├── reduce.js              - Reduce array to single value
│   ├── slice-splice.js        - Extract and modify arrays
│   ├── some-every.js          - Test array conditions
│   └── sort.js                - Sort array elements
├── string-methods/
│   └── string-methods.js      - Comprehensive string operations
├── object-methods/
│   └── object-methods.js      - Object manipulation and utilities
├── function-methods/
│   └── function-methods.js    - Function utilities and patterns
├── promise-methods/
│   └── promise-methods.js     - Asynchronous programming
├── utility-methods/
│   └── utility-methods.js     - General utility functions
└── index.js                   - Main entry point

🚀 Features

Each method implementation includes:

• ✅ Detailed explanation of how the method works
• ✅ Syntax and parameters with type information
• ✅ Return values clearly documented
• ✅ Practical examples with real-world scenarios
• ✅ Use cases demonstrating when to use each method
• ✅ Best practices and common pitfalls to avoid
• ✅ Custom implementations to understand internals
• ✅ Performance considerations and time/space complexity
• ✅ Edge cases and special behaviors
• ✅ Comparison with similar methods

📖 Method Categories

🔷 Array Methods (10 comprehensive files)

Transformation Methods

• map() - Transform each element and create new array
• filter() - Create new array with elements that pass a test
• reduce() - Reduce array to a single value
• flat() - Flatten nested arrays to specified depth
• flatMap() - Map and flatten in one operation

Search Methods

• find() - Find first element matching condition
• findIndex() - Find index of first matching element
• findLast() - Find last matching element (ES2023)
• findLastIndex() - Find index of last matching element (ES2023)
• includes() - Check if array contains a value
• indexOf() - Find first index of a value
• lastIndexOf() - Find last index of a value

Iteration Methods

• forEach() - Execute function for each element
• some() - Test if at least one element passes
• every() - Test if all elements pass

Manipulation Methods

• sort() - Sort array elements in place
• slice() - Extract portion without modifying original
• splice() - Add/remove elements (mutates array)

🔶 String Methods (Comprehensive coverage)

Search & Access Methods

• charAt() - Get character at specific index
• charCodeAt() - Get Unicode value at index
• indexOf() - Find first occurrence of substring
• lastIndexOf() - Find last occurrence of substring
• includes() - Check if string contains substring
• startsWith() - Check if string starts with substring
• endsWith() - Check if string ends with substring

Extraction Methods

• slice() - Extract part of string
• substring() - Extract substring
• substr() - Extract substring by length (deprecated)

Transformation Methods

• toLowerCase() - Convert to lowercase
• toUpperCase() - Convert to uppercase
• trim() - Remove whitespace from both ends
• trimStart() / trimEnd() - Remove whitespace from one end
• padStart() / padEnd() - Pad string to length
• repeat() - Repeat string n times

Replace & Split Methods

• replace() - Replace first occurrence
• replaceAll() - Replace all occurrences (ES2021)
• split() - Split string into array
• concat() - Concatenate strings

Pattern Matching Methods

• match() - Match against regex
• matchAll() - Get all regex matches (ES2020)
• search() - Search for regex pattern

🔸 Object Methods (Complete reference)

Object Creation & Copying

• Object.create() - Create object with specified prototype
• Object.assign() - Copy properties between objects (shallow)

Property Inspection

• Object.keys() - Get enumerable property names
• Object.values() - Get enumerable property values
• Object.entries() - Get [key, value] pairs
• Object.fromEntries() - Create object from entries
• Object.getOwnPropertyNames() - Get all property names
• Object.getOwnPropertyDescriptor() - Get property descriptor

Property Definition

• Object.defineProperty() - Define single property with descriptor
• Object.defineProperties() - Define multiple properties

Object State Modification

• Object.freeze() - Make object immutable
• Object.seal() - Prevent property addition/removal
• Object.preventExtensions() - Prevent new properties

Prototype Methods

• Object.getPrototypeOf() - Get object's prototype
• Object.setPrototypeOf() - Set object's prototype
• hasOwnProperty() - Check for own property

Utility Methods

• Object.is() - Same-value equality comparison
• Object.isFrozen() / isSealed() / isExtensible() - Check object state

🔹 Function Methods (Advanced patterns)

Context Methods

• call() - Invoke function with specific context
• apply() - Invoke function with arguments array
• bind() - Create bound function with fixed context

Higher-Order Functions

• Functions as arguments
• Functions returning functions
• Function composition
• Function piping

Advanced Patterns

• Closures - Data privacy and encapsulation
• Currying - Partial application of arguments
• Memoization - Caching function results
• Debouncing - Delay execution until idle
• Throttling - Limit execution frequency
• Decorators - Enhance function behavior

⚡ Promise Methods (Async programming)

Promise Creation

• Promise.resolve() - Create resolved promise
• Promise.reject() - Create rejected promise
• new Promise() - Create custom promise

Promise Combinators

• Promise.all() - Wait for all to resolve (fails fast)
• Promise.allSettled() - Wait for all to settle (ES2020)
• Promise.race() - Wait for first to settle
• Promise.any() - Wait for first to resolve (ES2021)

Async/Await

• async functions - Cleaner async syntax
• await operator - Wait for promise resolution
• Error handling with try/catch
• Parallel vs sequential execution

Advanced Patterns

• Retry logic
• Timeout patterns
• Circuit breaker
• Promise queues
• Batch processing

🛠️ Utility Methods (Comprehensive helpers)

Type Checking

• Type validators (isString, isNumber, isObject, etc.)
• Array type checking
• Null/undefined handling

Object Utilities

• Deep clone - Recursive object copying
• Deep equal - Recursive object comparison
• Deep merge - Merge nested objects
• Object validation

Array Utilities

• unique() - Remove duplicates
• flatten() - Flatten nested arrays
• chunk() - Split into chunks
• shuffle() - Random shuffle
• groupBy() - Group by property
• partition() - Split by predicate

String Utilities

• Case conversion - camelCase, kebab-case, snake_case
• Truncate - Limit string length
• Template - String interpolation
• Slug generation - URL-friendly strings
• HTML escape/strip - Security helpers

Number Utilities

• Random - Random number generation
• Clamp - Constrain to range
• Round - Precision rounding
• Format - Currency, number formatting
• Statistics - Average, median, std deviation

Date Utilities

• Format - Date formatting
• Add/subtract - Date arithmetic
• Comparison - Date differences
• Relative time - "2 hours ago" formatting

Validation Utilities

• Email validation
• Phone validation
• URL validation
• Credit card validation
• Password strength
• Custom validators

🏃‍♂️ Getting Started

Prerequisites

• Node.js (v12 or higher) or a modern web browser
• Basic understanding of JavaScript

Quick Start

1. Clone this repository

   git clone https://github.com/yourusername/javascript-programming-methods.git
   cd javascript-programming-methods

2. Explore method categories

   # Browse available methods
   ls array-methods/
   ls string-methods/
   ls object-methods/

3. Run examples

   # Run any method file
   node array-methods/map.js
   node string-methods/string-methods.js
   node promise-methods/promise-methods.js

💡 Usage Examples

Running Individual Method Files

Each file contains comprehensive examples and can be run independently:

# Array methods
node array-methods/filter.js
node array-methods/reduce.js
node array-methods/sort.js

# String methods
node string-methods/string-methods.js

# Promise methods
node promise-methods/promise-methods.js

Using in Your Projects

You can also import and use these methods as reference:

// Study the implementations and patterns
// Then apply them in your own code

// Example: Custom filter implementation
Array.prototype.customFilter = function(callback) {
    const result = [];
    for (let i = 0; i < this.length; i++) {
        if (callback(this[i], i, this)) {
            result.push(this[i]);
        }
    }
    return result;
};

📚 Learning Path

Beginner Level

1. Start with Array Methods: map(), filter(), forEach()
2. Learn String Methods: split(), join(), slice()
3. Understand Basic Object Methods: Object.keys(), Object.values()

Intermediate Level

1. Advanced Array Methods: reduce(), flat(), flatMap()
2. Function Methods: call(), apply(), bind()
3. Promise Basics: Promise.all(), async/await

Advanced Level

1. Advanced Patterns: Currying, Memoization, Composition
2. Complex Promise Patterns: Retry logic, Circuit breakers
3. Performance Optimization: Time complexity, Best practices

🎯 Key Features by File

File	Lines of Code	Key Concepts	Difficulty
filter.js	374	Filtering, Predicates, Performance	⭐⭐
map.js	255	Transformation, Immutability	⭐⭐
reduce.js	425	Accumulation, Complex operations	⭐⭐⭐
forEach.js	330+	Side effects, Iteration	⭐
find.js	380+	Searching, Short-circuiting	⭐⭐
some-every.js	400+	Boolean testing, Validation	⭐⭐
sort.js	450+	Sorting algorithms, Comparators	⭐⭐⭐
flat-flatMap.js	380+	Nested arrays, Flattening	⭐⭐
slice-splice.js	450+	Array manipulation, Mutation	⭐⭐
includes-indexOf.js	430+	Search methods, Performance	⭐⭐

🔍 What Makes This Different

• ✅ Not just documentation - Working code examples
• ✅ Custom implementations - Understand how methods work internally
• ✅ Real-world use cases - Practical applications
• ✅ Performance insights - Time/space complexity analysis
• ✅ Best practices - Common pitfalls and how to avoid them
• ✅ Comprehensive coverage - 100+ methods and patterns
• ✅ Modern JavaScript - ES2015+ features and latest standards
• ✅ Beginner to Advanced - Progressive learning path

💻 Browser Console Testing

You can also test these methods directly in your browser console:

// Open browser DevTools (F12)
// Copy and paste any example from the files

const numbers = [1, 2, 3, 4, 5];
const doubled = numbers.map(n => n * 2);
console.log(doubled); // [2, 4, 6, 8, 10]

🤝 Contributing

Contributions are welcome! Here's how you can help:

Ways to Contribute

• ⭐ Star this repository
• 🐛 Report bugs or issues
• 💡 Suggest new methods or improvements
• 📝 Improve documentation
• ✨ Add more examples and use cases
• 🔧 Fix typos or code improvements

Contribution Guidelines

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📖 Additional Resources

• MDN Web Docs - JavaScript
• JavaScript.info
• ECMAScript Specifications

🎓 Who Is This For?

• Beginners learning JavaScript fundamentals
• Intermediate developers looking to deepen their understanding
• Interview preparation - Common method questions
• Teachers/Educators - Teaching resources with examples
• Code reviewers - Reference for best practices

📊 Statistics

• Total Files: 10+ comprehensive implementations
• Total Examples: 200+ practical examples
• Methods Covered: 100+ JavaScript methods
• Lines of Code: 8,000+ lines of documented code
• Custom Implementations: 15+ from-scratch implementations

📝 License

This project is open source and available under the MIT License.

🌟 Star History

If you find this repository helpful, please consider giving it a star! ⭐

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Made with ❤️ for the JavaScript community

Happy coding! 🚀