code duplication in javascript

Question

Is there any tool to detect code duplication in JavaScript? I tried "PMD Duplicate code detector" but it is not supporting .js extension.

Answer 1

You can use JS Inspect it detects copy-pasted and structurally similar code, also supports *.js

Installation

npm install -g jsinspect

Run

jsinspect -t 50 ./path/to/src

Answer 2

I would recommend JSCPD

Installation

npm install -g jscpd

Run

jscpd ./path/to/code

(you have several type of reporters, default is console, but you can use html like this: jscpd -r html ./path/to/code )

Other solutions:

• JSinspect wasn't good for me because didn't support .ts and .tsx (jscpd supports 150+ formats
• InteliJ IDEs (I'm a big fan of them) don't seem to work since WebStorm found no duplicated code.

Answer 3

IDE can have this functionality. I use IntelliJ, this IDE has a built-in duplicate code checking mechanism at 2 scopes:

• Inline: Duplicate codes are underlined when opened in editor so that developer can easily catch and do refactoring.
• Analysis: Go to menu Analyze->Locate Duplicates.., specify scope to run through and list all duplications.

Answer 4

我建议看看这个线程（也在stackoverflow上）： Javascript源代码分析（特别是复制检查）