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A JIT compiler for JavaScript targetting x86-64 platforms.


  • D compiler (latest DMD recommended)
  • POSIX compliant OS (Linux, Unix, MacOS X)
  • Python 2.7 (if regenerating object layouts)
  • x86 64-bit CPU
  • 2 GB of RAM
  • GNU make
  • GNU time


Precompiled Docker Image

Higgs could be used as docker image.

Run docker run -ti dlanguage/higgs for the Higgs REPL. Run docker run -ti -v $(pwd):/work -w /work dlanguage/higgs your_local_file.js to evaluate a local .js-file.

Get the source:

git clone && cd Higgs/source

Compile a binary:

NOTE: if you run a non-Linux OS like FreeBSD you may not have GNU make installed. You may need to install the "gmake" package or otherwise acquire GNU make.

NOTE: if your default python version is 3.x, just append PYTHON=$PATH_TO_PYTHON2 to the make commands

make all generates a binary higgs in the source directory.

Compile a release binary:

make release generates a binary higgs in the source directoy.

Install (optional):

sudo make install generates a release binary using the release target, then copies the higgs binary to /usr/bin and the runtime files to /etc/higgs. The installation directories for the binary and runtime files may be changed with BIN_DIR and LIB_DIR respectively:

make install BIN_DIR=/my/bin/dir LIB_DIR=/my/lib/dir

sudo make install-dev is essentially the same as make install, but instead of copying the higgs binary and runtime files to your install directories, it creates symbolic links to your source folder.


make clean will remove any binaries in the source directory.

You may wish to run the unit tests:

make test generates a binary test-higgs and tests its proper functioning.

For further info, see the makefile.


higgs will start Higgs and give you a REPL (read-eval-print loop).

NOTE: if you did not run make install, then you must run higgs directly from the source directory, as otherwise it will not know where to find its runtime files.

To execute one or more files, pass them to higgs:

higgs file1.js file2.js

The --e option accepts a code string to execute:

higgs --e "var x = 4; x = x + 5; print(x)"

The --repl option will start a REPL after evaluating a string and/or files:

higgs --repl file1.js will evaluate file1.js and then start a REPL.

higgs file1.js will evaluate file1.js and then exit.

The --dumpasm option will dump the assembler code generated by the JIT to the console.

Command-line arguments can be passed to a JS script using the -- separator, as follows:

higgs file1.js file2.js -- 0 1 2

These arguments will be evaluated as JS code in the global scope and the resulting values inserted in a global arguments array.


  • You may wish to use rlwrap for a better REPL experience.
  • You will need to install libx11-dev to use the draw library, or to run the example programs.


Documentation for Higgs and included libraries can be found in the Higgs Wiki.

You can follow the development of Higgs on Maxime's blog.