A popular and effective programming language for developing dynamic and interactive web applications is JavaScript. JavaScript code is simple to write, but it's also simple to make mistakes, which can result in bugs, security flaws, and performance problems. We'll go over 10 common blunders in writing JavaScript code in this article.
![10 Common Mistakes to Avoid When Writing JavaScript Code]()
1. Not Using Strict Mode
A "strict mode" in JavaScript imposes more stringent guidelines for code execution. It assists in identifying common mistakes and stops some risky behaviors. However, it is not utilized by many developers. Add the next line to the top of your JavaScript file to enable strict mode:
2. How to Use Global Variables
Global variables are frequently used incorrectly, which can result in bugs and unexpected behavior. Any function in your code can access global variables and make changes to them. Always declare your variables inside functions, or use the let or const keywords to declare them inside a block, to avoid using global variables.
3. Absence of Semicolons
Semicolons are not necessary for JavaScript, but leaving them out can lead to errors and make your code more difficult to read. When ending statements in your code, use semicolons.
4. Unable to handle errors
When something goes wrong, such as when a variable is undefined or a function call fails, JavaScript code has the ability to throw errors. Failure to address these errors may result in erratic behavior and crashes. Always use error-handling functions or try-catch blocks to handle errors in your code.
5. Overuse of eval()
The JavaScript function eval() enables you to run code contained in a string. However, using eval() can be risky and leave your program open to security flaws. Find alternatives whenever possible and stay away from using eval().
6. Refraining from Comparing with '==='
The '==' and '===' comparison operators are available in JavaScript. Type coercion is carried out by the '==' operator but not by the '===' operator. When comparing values of various types, the absence of the equal sign '===' can result in unexpected behavior. For strict equality comparisons, always use '==='.
7. Absence of the const and let
Var, Let, and Const are the three keywords available in JavaScript for declaring variables. Var is a dated keyword with peculiarities that can result in bugs. Instead, use let for variables that will change and const for constants that won't change.
8. Absence of setTimeout() Correctly
Using the JavaScript function setTimeout(), you can instruct a function to start running after a specified period of time. However, improper use can result in bugs and performance problems. Always use the setTimeout() method with a function or an arrow function as the first argument, and specify the delay in milliseconds with the second argument.
9. Not Using the Correct Formatting and Indentation
If JavaScript code is not properly formatted and indented, it may be difficult to read and debug. To make your code more readable and maintainable, maintain consistency in your coding style and adhere to industry best practices.
10. Failure to test your code
Finally, failing to test your code is a frequent error that can result in bugs and strange behavior. Always thoroughly test your code to find bugs and make sure it functions as intended.
In conclusion, JavaScript is a strong language, but when writing code, it's critical to avoid common mistakes. You can develop reliable, secure, and maintainable JavaScript applications by adhering to best practices and employing sound coding techniques.