JavaScript Analyzer

About JavaScript Analyzer

The JavaScript Analyzer is a free, browser-based source-code analysis tool designed to help developers quickly understand the size, structure and composition of JavaScript code. It calculates practical metrics such as line counts, comments, characters, functions, variables, strings and numeric literals, then provides additional information about common language features.

This tool is useful when reviewing an existing script, checking a file before optimization or JavaScript obfuscation, comparing changes between versions, or getting a quick overview of unfamiliar JavaScript. It focuses on readable source-code information rather than executing the code.

What Does This JavaScript Analyzer Check?

After you run an analysis, the tool can report several categories of information from the JavaScript source you provide. The available results include:

• Total lines and code lines to give you a quick indication of source-code size.
• Comment lines to help you understand how much of the file is documentation or commented code.
• Character count for a simple measurement of the source text.
• Function and arrow-function usage to show common function structures.
• Variable declarations and other basic source statistics.
• String and numeric literal counts.
• Classes, imports and exports where supported by the analyzer's pattern checks.
• Promises, async functions and await expressions.
• Try/catch structures and loops.
• Common code-quality patterns reported by the analyzer.

How To Use the JavaScript Analyzer

1. Paste the JavaScript source code you want to inspect into the input box.
2. Click Analyze Code to process the source text.
3. Review the summary statistics, including lines, comments, characters, functions, variables, strings and numeric literals.
4. Review the detailed structure and language-feature results.
5. Check the available code-quality results for additional patterns identified by the tool.

If you want to test the analyzer before using your own code, select Load Sample. To remove the current input and start again, select Clear.

Understanding the Analysis Results

The statistics shown by this tool are intended as a quick source-code overview. For example, total lines represent the overall line count, while code lines and comment lines help separate source text from comments. Function, variable, string and numeric counts can help you estimate the composition of a script.

The detailed analysis provides another level of information by grouping supported patterns into structure and language features. This can make it easier to inspect an unfamiliar file before refactoring, optimizing or preparing it for another development task.

Analyze JavaScript Before You Use a JavaScript Obfuscator

Before you obfuscate JavaScript code, it helps to know what you are protecting. Running your script through the analyzer first shows how large it is, how many functions and strings it contains, and how much of the file is comments. This is a practical first step in any workflow that uses a JavaScript obfuscator or a JS obfuscator.

• Check the size: note the character and line counts so you can compare them with the obfuscated result later.
• Spot leftover code: comment lines and unused sections can be removed before you obfuscate JS.
• Review strings: string literals are often what an obfuscator hides, so a high string count tells you how much text will be encoded.
• Review structure: function, class and async counts help you understand what the obfuscator JavaScript tool will need to transform.

When you are ready, use the free JavaScript obfuscator online on ObfuscatorJS to transform a copy of your code, and keep your original source in version control.

Analyzing Obfuscated JavaScript

The analyzer is also helpful when you receive a script that has already been processed by a JavaScript code obfuscator. Because the tool only reads the text and never runs it, you can inspect the code's metrics without executing anything you do not trust.

Obfuscated code often looks different from normal source code. Typical signs include very few or no comment lines, many string literals, very long lines, and many functions with short or meaningless names. These signs are only hints, and a normally minified file can look similar, but they give you a quick sense of how heavily a script has been transformed by JavaScript obfuscation.

Heavily obfuscated code may produce unusual results, because the analyzer relies on the source patterns it supports. Treat the numbers as an overview rather than an exact description of what the script does.

Compare Code Before and After Obfuscation

You can analyze your script twice, once before and once after you use an obfuscator, and compare the results. Look at the character count to see how much the file size changed, at the comment count to confirm comments were removed, and at the string count to see how strings were moved or encoded. Stronger obfuscation settings usually produce a larger and slower file, so these numbers help you find a balance between protection and performance.

Can You Encrypt JavaScript?

Many developers search for a way to encrypt JavaScript, but code that runs in a browser cannot be truly encrypted, because the browser has to read it in order to run it. Obfuscation is the practical alternative. It makes code much harder for people to understand, but it is a deterrent rather than a lock. If you want to protect JavaScript source code, obfuscate a copy of it, test the result carefully, and keep passwords, API secrets and security-critical logic on a trusted server.

JavaScript Analyzer vs. a JavaScript Linter

A code analyzer and a linter serve different purposes. This analyzer is primarily intended to provide source metrics and identify the supported patterns listed on this page. A dedicated JavaScript linter can perform deeper syntax and style checks, apply configurable coding rules and report many issues that a simple metrics-based analyzer does not attempt to detect.

Therefore, the results from this tool should be treated as a quick analysis rather than a complete assessment of JavaScript correctness, security or performance.

JavaScript Analyzer vs. Code Execution

An important distinction is that source-code analysis does not require executing the code. The analyzer examines the JavaScript text to calculate metrics and identify supported patterns. It is not intended to run functions, access your application's runtime state or reproduce the behavior of your program.

Privacy

Your JavaScript code is analyzed directly in your browser. The tool does not require an account or server-side upload for the analysis described on this page. Because source code can contain private business logic, API-related code or other sensitive information, you should still review the code you paste into any online service before using it.

Limitations

JavaScript is a large and evolving language, and simple source-pattern analysis cannot understand every possible program structure. Results may vary for unusual syntax, generated code, heavily compressed code, dynamically constructed source, or patterns that are outside the analyzer's supported checks.

The analyzer should therefore be used as a convenient source-code overview. It should not be considered a substitute for a complete parser, compiler, debugger, security audit or dedicated linting tool.

More Tools for JavaScript Developers

ObfuscatorJS brings together tools for the whole JavaScript workflow. Use the JavaScript obfuscator tool to make your code harder to read, explore the full collection of ObfuscatorJS developer tools for formatting, validation and encoding, and use this analyzer to understand your code before and after you change it. Whether you need a quick js obfuscator online, an obfuscator js online workflow, or simply a reliable way to inspect a script, you can find it in one place. Developers who know the open-source javascript-obfuscator package can also use this page to check the output of their own build pipeline.

Frequently Asked Questions