According to the survey, 41% of JS developers who currently offer their services on the market have less than 5 years of experience in coding. While this article may not be a revelation for programmers with broad experience, it will most certainly come in handy for those of you who are still at the beginning of their career path.
In the list below, we have collected some of the most common mistakes that almost all JS developers make. Read them carefully to make sure you are not making them as well:
1. Semicolons vs. Commas
Expert developers often use semicolons to keep their code readable. That’s where most beginners make the same big mistake – they believe that semicolons can consume additional memory and, thus, harm the product’s performance. Keeping this faulty belief in mind, they often tend to use commas instead of semicolons.
This is the first common mistake you can avoid. Studies show that additional variable declarations and semicolons do not affect the performance or speed of applications. However, they can help keep your code readable and clean. Thus, there are no reasons to avoid using semicolons.
2. Confusing “=” and “==” Operators
The assignment “=” and comparison “==” operators are often confused by beginners. To avoid this mistake, keep in mind when to use each operator:
- “=” – to assign values to a variable;
- “==” – to compare the value of a variable conditionally.
Adding, modifying, removing elements, or otherwise manipulating the DOM is pretty easy in JS. However, it should be done efficiently.
Another common mistake made by programmers is inefficient DOM manipulation. For example, one of such cases can be adding multiple elements one at a time – such an approach is expensive, inefficient, and is not likely to work well. A better solution would be to use document fragments instead – this will help you boost performance and efficiency at the same time.
4. Not Getting the Most of the + Symbol
- To add variables;
- To concatenate strings.
Often, beginners forget about the multiple purposes of this symbol and, thus, use it inaccurately. This is one more mistake to watch out for.
5. Misunderstanding the “Strict Mode”
Just in case you are wondering what it is in a nutshell, a “strict mode” (which can be used by adding [‘use strict’ ;] at the beginning of your source files) allows you to enforce stricter error handling and parsing on your code at runtime, and to make it more secure.
There are quite a few benefits of the “strict mode,” but many beginners tend to overlook them, which is another typical JS mistake.
6. Using Named Indexes to Define Array Objects
7. Block Level Scope to Define Variables
8. Not Loading the Code before Referencing
9. Using “This” Incorrectly
One more typical mistake is improper use of a keyword “this.” The biggest problem here is that the value of this keyword can vary in the runtime, depending on the code’s context. To avoid this mistake, a programmer should always keep an eye on the context and keep in mind the different possible meanings of “this” keyword.
10. Forgetting to Check whether an Object is Undefined
Bottom Line: How To Avoid Common Mistakes?
How to avoid making these typical mistakes? The easiest way to avoid them and become a better specialist is by learning from others’ experiences. Of course, there is no way you can ensure an absolute absence of failures in your career. After all, failures and mistakes are what help a beginner to become a better professional. However, knowing about the most common mistakes, you can minimize the chances of repeating them and develop as a professional much faster. Hopefully, this article will help you!