Supported Formats

Overview

jscpd supports 223 programming languages and document formats for duplication detection.

130 formats are auto-detected by file extension. 88 registered formats have a grammar but no built-in extension mapping — use --formats-exts or --formats-names to activate them. An additional 5 formats (clike, comments, hpkp, hsts, keymap) are internal grammar dependencies.

Cross-Format Tokenizers

These formats use bespoke multi-block tokenizers that extract embedded code sections and resolve each block to the correct sub-format, enabling cross-format duplicate detection — e.g. a <script> block in a .vue file matched against .ts files.

Auto-Detected Formats

These formats are detected automatically by file extension — no extra flags needed.

General-Purpose Languages

Registered Formats (No Extension Mapping)

These formats have a working grammar but no built-in file extension mapping. Use --formats-exts to associate extensions, or --formats-names for extensionless files.

# Example: enable ABAP detection for .abap files
jscpd --formats-exts "abap:abap" ./src

# Example: detect Dockerfiles by name
jscpd --formats-names "docker:Dockerfile" ./src

Extension Detection Only (No Grammar)

These formats register file extensions for detection but have no bundled grammar — tokenization returns an empty array. They still benefit from jscpd's blank-line and structural matching.

Shebang Detection

jscpd can detect duplications in script files that have no file extension by reading the #! shebang line:

Custom Format Extensions

Associate custom file extensions with a format:

jscpd --formats-exts "javascript:js,es6,vue" ./src

Or in configuration:

{
  "formatsExts": {
    "javascript": ["js", "es6", "vue"]
  }
}

Custom Filename Mapping

Map extensionless files to a format by filename:

jscpd --formats-names "makefile:Makefile,GNUmakefile;docker:Dockerfile" ./src

Or in configuration:

{
  "formatsNames": {
    "makefile": ["Makefile", "GNUmakefile"],
    "docker": ["Dockerfile"]
  }
}

View Full List

You can also view the full list of supported formats by running:

jscpd --list