One technique is to use console.log statements to output the values of variables and expressions to the console. This can help you understand what is happening in your code and identify any problems.
Another technique is to use the debugger keyword to pause the execution of your code and inspect the values of variables and expressions. You can use the debugger in conjunction with a debugger tool in your code editor or browser to step through your code and see what is happening at each line.
You can also use the "console.table" method to output the contents of an array or object to the console in a tabular format, which can make it easier to see the values of multiple variables at once.
Another technique is to use a linter, which is a tool that checks your code for syntax errors and other problems. A linter can help you catch mistakes that you might have missed and ensure that your code is consistent with best practices.
Finally, it is a good idea to write unit tests for your code, which are small, isolated tests that verify the behavior of individual functions or components. Unit tests can help you catch bugs early in the development process and ensure that your code is working as expected.