Why JavaScript Is Bad: Common Criticisms and Their Solutions

Many developers ask "why JavaScript is bad" when encountering its unique quirks and limitations. While JavaScript powers the modern web, it has legitimate design flaws that can frustrate developers. Understanding these criticisms helps you write better code and avoid common pitfalls.

Common Criticisms of JavaScript #

1. Weak Type System #

JavaScript's dynamic typing leads to unexpected behavior and runtime errors.

// Type coercion creates confusing results
console.log('5' + 3);        // "53" (string concatenation)
console.log('5' - 3);        // 2 (numeric subtraction)
console.log(true + 1);       // 2
console.log(false + 1);      // 1
console.log([] + []);        // "" (empty string)
console.log({} + {});        // "[object Object][object Object]"

Solution: Use TypeScript or strict equality operators and explicit type checking.

// Better approach with explicit checks
function addNumbers(a, b) {
    if (typeof a !== 'number' || typeof b !== 'number') {
        throw new Error('Both arguments must be numbers');
    }
    return a + b;
}

// Use strict equality
if (value === 0) { /* ... */ }  // Good
if (value == 0) { /* ... */ }   // Avoid - type coercion

2. Global Scope Pollution #

Variables without proper declaration become global, causing naming conflicts.

// Problematic code - creates global variables
function badFunction() {
    globalVar = "I'm accidentally global!";  // Missing 'var', 'let', or 'const'
    for (i = 0; i < 10; i++) {              // 'i' becomes global
        // code here
    }
}

badFunction();
console.log(globalVar); // "I'm accidentally global!"
console.log(i);         // 10

Solution: Always use proper variable declarations and strict mode.

'use strict';

function goodFunction() {
    const localVar = "I'm properly scoped!";
    for (let i = 0; i < 10; i++) {
        // 'i' is block-scoped
    }
}

3. Confusing 'this' Context #

The this keyword behaves unpredictably depending on how functions are called.

const obj = {
    name: 'MyObject',
    regularFunction: function() {
        console.log(this.name); // "MyObject"
        
        setTimeout(function() {
            console.log(this.name); // undefined (in strict mode) or global object
        }, 100);
    }
};

obj.regularFunction();

Solution: Use arrow functions or explicit binding.

const obj = {
    name: 'MyObject',
    regularFunction: function() {
        console.log(this.name); // "MyObject"
        
        // Arrow function preserves 'this' context
        setTimeout(() => {
            console.log(this.name); // "MyObject"
        }, 100);
        
        // Or use explicit binding
        setTimeout(function() {
            console.log(this.name); // "MyObject"
        }.bind(this), 100);
    }
};

4. Asynchronous Complexity #

Callback hell and Promise chains can make code difficult to read and maintain.

// Callback hell example
getData(function(a) {
    getMoreData(a, function(b) {
        getEvenMoreData(b, function(c) {
            getFinalData(c, function(d) {
                // Finally got all data
                console.log(d);
            });
        });
    });
});

Solution: Use async/await or proper Promise chaining.

// Modern async/await approach
async function fetchAllData() {
    try {
        const a = await getData();
        const b = await getMoreData(a);
        const c = await getEvenMoreData(b);
        const d = await getFinalData(c);
        console.log(d);
    } catch (error) {
        console.error('Error fetching data:', error);
    }
}

5. Inconsistent Array Methods #

Some array methods mutate the original array while others return new arrays.

const numbers = [3, 1, 4, 1, 5];

// Mutating methods (change original array)
numbers.sort();     // [1, 1, 3, 4, 5] - numbers is changed
numbers.push(9);    // [1, 1, 3, 4, 5, 9] - numbers is changed

// Non-mutating methods (return new array)
const doubled = numbers.map(n => n * 2);  // numbers unchanged
const filtered = numbers.filter(n => n > 2); // numbers unchanged

Solution: Learn which methods mutate and consider using immutable approaches.

// Immutable approach
const originalNumbers = [3, 1, 4, 1, 5];

// Create new sorted array without mutating original
const sortedNumbers = [...originalNumbers].sort();

// Use spread operator for safe mutations
const numbersWithNine = [...originalNumbers, 9];

Performance Issues #

Memory Leaks #

JavaScript's garbage collector can't always clean up references automatically.

// Potential memory leak with closures
function createLeak() {
    const largeData = new Array(1000000).fill('data');
    
    return function() {
        // This closure keeps largeData in memory
        console.log('Function called');
    };
}

const leakyFunction = createLeak(); // largeData stays in memory

Solution: Be mindful of closures and clean up references.

function createClean() {
    let largeData = new Array(1000000).fill('data');
    
    return {
        execute() {
            console.log('Function called');
        },
        cleanup() {
            largeData = null; // Explicitly release memory
        }
    };
}

Modern JavaScript Improvements #

Many criticisms of why JavaScript is bad stem from legacy features. Modern JavaScript (ES6+) addresses many issues:

• Block-scoped variables: let and const instead of var
• Arrow functions: Consistent this behavior
• Modules: Better code organization
• Classes: More familiar OOP syntax
• Template literals: Better string formatting
• Destructuring: Cleaner variable assignment

Best Practices to Avoid JavaScript Problems #

1. Use a linter (ESLint) to catch common mistakes
2. Enable strict mode ('use strict';)
3. Consider TypeScript for type safety
4. Use modern JavaScript features (ES6+)
5. Follow consistent coding standards
6. Write comprehensive tests
7. Use proper error handling

Summary #

While JavaScript has legitimate flaws that explain why some developers think JavaScript is bad, most issues can be avoided with modern practices and tools. Understanding these criticisms makes you a better JavaScript developer by helping you:

• Avoid common pitfalls and anti-patterns
• Write more predictable and maintainable code
• Choose the right tools and approaches for your projects
• Appreciate why modern JavaScript features exist

The key is not to avoid JavaScript because of its problems, but to learn how to use it properly and leverage modern tools that address its weaknesses.