JavaScript Tips and Best Coding Practices

JavaScript Tips

JavaScript is one of the most widely used programming languages for web development. It’s the most popular and highly paid language of 2020, and the demand for it is only likely to increase in the coming years. If you want to know more about the most popular coding languages including JavaScript, follow the link: https://litslink.com/blog/top10-important-coding-languages-2020

Below are some tips for JavaScript development that can help you get started and improve your coding practices.

1. Comment Your Code

JavaScript allows you to add inline comments to document your thought process. It’s crucial to comment the code as you go because it will help you and your team members to understand how it works after some time passes. Commenting is an essential practice that needs to become a habit.

2. Use === Instead of ==

Operators === and == are almost equivalent in JavaScript. However, the latter does an automatic type conversion when needed, while the former simply matches the type and value. It’s a good practice to use === for testing conditions. Besides, it works faster than ==.

3. Limit the Use of Global Variables

Declare your variables with var before assigning them any values. After declaring the variable, you can control whether to put it in the global or function-level scope. Try to reduce the number of global variables in your code, as it helps limit unintended interactions with other libraries, applications, and so on.

4. Scripts Should be at the Bottom

Place all JavaScript files for functionality before the closing body tag instead of stuffing them at the top. This will help reduce the time it takes your page to load.

5. Avoid Using eval()

The eval() method allows the execution of any code at runtime. Since it gives access to the compiler, the method significantly decreases the security and performance of the application. Replacing eval() with other approaches can help secure the code from injection attacks and sloppy execution.

6. Use [splice] Instead of [delete]

The delete method is good to delete a property of an object. To remove an item from an array, it’s better to use splice. When delete is applied for this purpose, it replaces the object that you want to remove with the value undefined instead of deleting it from the array completely.

7. JavaScript is Case-Sensitive

Many new developers tend to forget that JavaScript is case-sensitive, which results in errors. For instance, in JS “testVariable” and “TestVariable” represent two different variables, unlike in many other programming languages. To avoid confusion, give each variable a unique and descriptive name instead of relying solely on the differences in the case of the word.

8. Look Out for Reserved Words

In addition to keeping the case in check, you should remember to avoid using reserved keywords as variable names. Examples include while, for, if, as well as many functions and object properties, such as toArray() and others.

9. Don’t Omit Semicolons

Most modern browsers will still recognize JavaScript code correctly when developers don’t use semicolons. However, sometimes, the negligence to use one can result in unexpected bugs that are incredibly hard to find and fix. Build a habit to use semicolons when appropriate, and your code will be more safe and readable.

10. Use Raw Code when Applicable

JavaScript offers a huge number of libraries for various tasks, and you should definitely use them when creating your applications. However, it’s also important to remember that no library operates faster than the equivalent function in a piece of raw JS code. Assess your needs and the scope of what you need to create before opting for a library instead of coding a function from scratch.

11. Use map() to Loop Through an Array

To iterate over an array, use the map() method instead forEach(). Unlike forEach(), map() returns a new array.

12. Look Out for Issues with the Floating Point

In JavaScript, 0.1 + 0.2 is equal to 0.30000000000000004 instead of simply 0.3. This occurs because floating-point numbers are represented in 64-bit binary, according to IEEE 754 standard. To avoid or fix problems triggered by this property, use toFixed() or toPrecision() functions.

13. Beware of the [with] Statement

The with statement allows developers to access deeply nested objects and insert new ones at the front of the scope chain. This can frequently result in errors. Instead, use var to help avoid bad behavior by creating references to reused objects.

14. Watch out for SetTimeOut() and SetInterval() Errors

Some developers make the mistake of passing a string value to functions SetInterval() and SetTimeOut() as a parameter. You should never pass a string to these functions. Such code will functionally run like eval() does, compromising security, and it’s also inefficient. Instead, always pass a function name.

15. Avoid Inverting Variable Type

In JavaScript, it is possible to change the type of the variable after initializing it. Consider this code:

var test = “apple”;
test = 5;

No browser would object to running this code properly, but this practice is dangerous as it can produce substantial bugs in large applications.

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