How to read JavaScript errors

With the rapid development of Web technology, JavaScript has become the core language of front-end development. However, during the development process, we always encounter various JavaScript errors, and many developers do not know how to solve these errors. This article will introduce some common JavaScript errors and provide solutions.

1. Syntax Error (syntax error)
Syntax error is one of the most common errors when writing code. It indicates that the code has a syntax problem. Syntax errors occur when the code contains common errors such as spelling errors, mismatched brackets, invalid characters, missing semicolons, etc.
Solution:
Check the code carefully, especially those parts that don't look correct. See the exact description of the syntax error and fix it, which is usually part of the error message used in the console.

2. Reference Error
A reference error means that you are trying to access a variable or object that does not exist. This usually happens when a variable is misspelled or the variable is used before it lacks the correct reference.
Workaround:
Before using variables, make sure they are actually defined. If possible, consider using default variables or accessing object properties to protect yourself from reference errors.

3. Type Error (type error)
Type error is another common type of error. It means you are trying to use the wrong type of data or method. For example, try calling an integer method from a string variable or passing an object to a function that expects a pure data value.
Solution:
Understand which types your code needs to use and make sure all variables and objects are of the correct type. Try to avoid passing objects of unsupported data types to functions or methods.

4. Range Error (range error)
A range error means that you are trying to use a numeric value that is out of range. This happens when trying to assign a numeric value larger than JavaScript's integer range (2¹⁵-1 to -2¹⁵).
Workaround:
Make sure that your code does not use numeric values ​​that are outside the range of values ​​that JavaScript can handle. Using the BigInt type solves this problem.

5. URI Error (URI error)
URI error means that you are trying to use the wrong URI method and format. For example, an error occurs when you use unsafe characters in a URI.
Workaround:
Make sure your URI conforms to the URI format and use the encodeURIComponent or encodeURI function to convert unsafe characters. Make sure not to pass data to the URI that exceeds the allowed length.

6. Eval Error (parsing error)
Eval Error is the most serious error type in JavaScript, indicating that a parsing error occurred during runtime. This usually happens when trying to use the eval() function.
Solution:
Use strict implementation methods to avoid using eval. If you must use eval, make sure it is not affected by malicious code, which may cause runtime errors.

In short, JavaScript errors are inevitable during the development process. However, as long as we understand these error types and their solutions, we can solve problems faster and more accurately and improve programming efficiency. Hope this article helps you!

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