1. Global Variables:
   • Problem: Forgetting to usevar,let, orconst can create global variables unintentionally.
   • Solution: Always declare variables withlet orconst.

// Badx=10;// Goodletx=10;

1. Variable Hoisting:
   • Problem: Variables declared withvar are hoisted to the top of their scope, which can lead to unexpected behavior.
   • Solution: Uselet andconst to avoid hoisting issues.

console.log(x);// undefinedvarx=5;// Use let or constconsole.log(y);// ReferenceError: y is not definedlety=5;

1. Function Hoisting:
   • Problem: Function declarations are hoisted, but function expressions are not.

// This worksgreet();functiongreet(){console.log('Hello');}// This does not worksayHi();// TypeError: sayHi is not a functionvarsayHi=function(){console.log('Hi');};

1. this Keyword:
   • Problem: The value ofthis can change depending on the context in which a function is called.
   • Solution: Use arrow functions or.bind() to maintain the correctthis context.

functionPerson(name){this.name=name;setTimeout(function(){console.log(this.name);// undefined},1000);}// Using arrow functionfunctionPerson(name){this.name=name;setTimeout(()=>{console.log(this.name);// Correctly logs the name},1000);}

1. Equality Operators:
   • Problem: The== operator performs type coercion, which can lead to unexpected results.
   • Solution: Use the=== operator for strict equality checks.

console.log(0=='0');// trueconsole.log(0==='0');// false

1. Falsy Values:
   • Problem: Understanding what values are considered falsy (false,0,'',null,undefined,NaN).
   • Solution: Be mindful when checking for truthy or falsy values.

if(0){console.log('This will not run');}

1. Closure Scope:
   • Problem: Loop variables in closures can lead to unexpected behavior.
   • Solution: Uselet in loops to ensure block scope.

for(vari=1;i<=3;i++){setTimeout(function(){console.log(i);// Logs 4, 4, 4},i*1000);}// Using letfor(leti=1;i<=3;i++){setTimeout(function(){console.log(i);// Logs 1, 2, 3},i*1000);}

1. Default Parameters:
   • Problem: Older JavaScript versions don't support default parameters.
   • Solution: Use ES6 default parameters or logical operators.

functiongreet(name){name=name||'Guest';console.log('Hello'+name);}// ES6 Default parametersfunctiongreet(name='Guest'){console.log(`Hello${name}`);}

1. Array Methods:
   • Problem: Confusingmap,forEach,filter,reduce.
   • Solution: Understand the purpose and return values of each method.

constnumbers=[1,2,3,4];numbers.forEach(n=>console.log(n));// Logs each numberconstdoubled=numbers.map(n=>n*2);// Returns [2, 4, 6, 8]constevens=numbers.filter(n=>n%2===0);// Returns [2, 4]constsum=numbers.reduce((total,n)=>total+n,0);// Returns 10

1. Async/Await:

   • Problem: Misunderstanding how to handle asynchronous code.
   • Solution: Useasync andawait for cleaner asynchronous code.

   asyncfunctionfetchData(){try{constresponse=awaitfetch('https://api.example.com/data');constdata=awaitresponse.json();console.log(data);}catch(error){console.error('Error fetching data',error);}}

Understanding these common pitfalls can help you write more robust and maintainable JavaScript code. If you have any specific scenarios or examples you'd like to delve into, feel free to ask!