How to compress obfuscated javascript

With the popularity of the Internet, JavaScript, as a widely used programming language, is widely used in the development of websites and applications. However, since JavaScript itself is a text programming language, the source code file is relatively large, which will slow down the loading speed of web pages. In addition, since Javascript is a client-side scripting language, the client browser needs to translate a large amount of script code, which will occupy the CPU resources of the client system and consume the battery, resulting in a decline in user experience. Therefore, in actual development, we Compression and obfuscation technology is needed to convert JavaScript code into a compressed or obfuscated version to improve the loading speed and user experience of web pages.

In this article, we will discuss two common methods of how to compress Javascript code: compression and obfuscation, as well as their advantages and disadvantages.

1. Compression of Javascript code

Javascript code compression refers to removing irrelevant characters such as spaces, comments, line breaks, etc. from the Javascript source code to reduce the size of the Javascript source code. . Compression can be achieved using various wrappers and tools, such as UglifyJS, YUI Compressor, and many more.

Advantages:

1. Improve web page loading speed: By removing and shrinking spaces, comments, and other characters in Javascript code, compression can reduce the size of the file and ease its transfer to The bandwidth and time required on the user's computer.
2. Improving SEO rankings: Compressing Javascript code can minimize the number of bytes transmitted to serve web pages, thereby helping search engines retrieve and render your web pages faster and improve your SEO rankings.
3. Reduce bandwidth usage: By compressing Javascript code, you can reduce the amount of data transmitted between the browser and the server and reduce overall bandwidth usage. Reduce network traffic and save your company's broadband costs.
4. Protect trade secrets: Since the Javascript code is compressed, unauthorized computer users cannot directly read and copy the content in the code, thereby protecting the confidentiality of key codes.

Disadvantages:

1. Difficulty in debugging and maintenance: Compressed Javascript code is often difficult to read and understand, which makes debugging and maintenance more difficult.
2. Poor code readability: The compressed Javascript code may no longer be as readable as the original version. Also, because the compressor removes comments and whitespace from the code, it can be difficult to determine the exact purpose of the code or update the history.
3. Version Control Issues: During version control, since compressed Javascript files are frequently changed, it may not be easy to determine the exact version of the file.

2. Javascript code obfuscation

Javascript code obfuscation refers to processing the Javascript source code to make it difficult to understand and modify to avoid risks such as code leakage or destruction. Obfuscation technology uses various tools, such as Javascript Obfuscator, etc., to reorganize, randomize, rename and encrypt variables, functions, objects, strings and numbers of Javascript code, and delete useless code.

Advantages:

1. Improve code security: obfuscation technology can encrypt Javascript code and disrupt the code structure, making the decompilation and reverse engineering process difficult, improving code security.
2. Prevent attacks: Through obfuscation, you can prevent attackers from realizing the function and purpose of the code. Obfuscation can reduce the risk of attacks and improve code security.
3. Increase code difficulty: obfuscation technology can reorganize, randomize, rename and encrypt the code in various ways, thereby increasing the complexity and difficulty of the code, making it difficult for hackers to crack the code .

Disadvantages:

1. Performance loss: Since obfuscation technology encrypts and reconstructs Javascript code multiple times, it may reduce the execution efficiency and performance of the code.
2. Unmaintainable: Due to confusion, the code becomes difficult to understand and maintenance becomes more difficult, which will increase development costs and difficulty.
3. Poor readability: Code confusion will make the code difficult to understand and read, which will make subsequent code upgrades and maintenance difficult.

Summary:

In the engineering practice of Javascript code, compression and obfuscation are not actually competitive, but complementary. In practical applications, compression and obfuscation technologies can be used at the same time, such as using UglifyJS for compression and Javascript Obfuscator for obfuscation, to maximize the confidentiality of Javascript code and improve the execution efficiency and performance of the code.

However, before applying compression and obfuscation techniques, we need to be aware of the limitations of compression and obfuscation techniques. They don't completely secure Javascript code: they reduce the risk of code leakage and corruption, but they don't completely eliminate those risks. Therefore, in addition to compression and obfuscation technologies, we also need to adopt other security measures, such as authentication, authorization, encryption and other technologies, to achieve higher security standards.

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