Javascript Common Error Messages and Fixes

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Debugging is an essential part of programming, and JavaScript is no exception. When you encounter errors in your code, it's crucial to understand the error messages you receive and how to fix them. Let's dive into some common JavaScript error messages and their solutions.

ReferenceError: Undefined Variable

This error occurs when you try to use a variable that hasn't been declared or is misspelled. For example:

console.log(nonExistentVariable);

To fix this error, make sure the variable is correctly spelled and declared before using it. In this case, declare nonExistentVariable first:

let nonExistentVariable = "Hello, JavaScript!";
console.log(nonExistentVariable);

TypeError: Cannot read property 'x' of undefined

This error typically occurs when you try to access a property or method on an undefined object. For example:

let user;
console.log(user.name);

To fix this error, ensure the object is properly defined before accessing its properties:

let user = {
    name: "John Doe"
};
console.log(user.name);

SyntaxError: Unexpected token

This error usually indicates a syntax issue, such as a missing parenthesis, semicolon, or curly brace. For example:

function greet() {
    console.log("Hello, JavaScript!"
}

In this case, the error occurs because a closing parenthesis is missing after the console.log statement. To fix it, add the missing parenthesis:

function greet() {
    console.log("Hello, JavaScript!");
}

RangeError: Maximum call stack size exceeded

This error occurs when a function calls itself recursively without a terminating condition, causing an infinite loop. For example:

function recursiveFunction() {
    recursiveFunction();
}

recursiveFunction();

To fix this error, ensure your recursive function has a terminating condition:

function recursiveFunction(n) {
    if (n <= 0) {
        return;
    }
    console.log(n);
    recursiveFunction(n - 1);
}

recursiveFunction(5);

URIError: Malformed URI

This error occurs when you pass an incorrect URI to methods like encodeURI() or decodeURI(). For example:

let malformedURI = "https://%test.com";
console.log(decodeURI(malformedURI));

To fix this error, make sure the URI is correctly formatted before passing it to the method:

let validURI = "https://test.com";
console.log(decodeURI(validURI));

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