Warning: Reason support is experimental. We are looking for beta-tester and contributors.

Main Command-Line options

Option name Description
-version Display the version of the compiler
-vnum Display the version number of the compiler
-o <file> Set the output filename to <file>
-sourcemap Generate sourcemap
-opt {0,1,2,3} Set the compilation profile (default 1). See Optimization section below.
-tc {none,trampoline} Set the tailcall optimisation (default trampoline)
-pretty Pretty print javascript output
-noinline Disable code inlining
-debuginfo Output debug information
-I dir Add <dir> to the list of include directories
-file file[:dir] Register <file> to the pseudo filesytem and choose the the destination directory <dir> (default /)
-noruntime Do not include the runtime
-linkall Link all primitives
-toplevel Compile a toplevel
-enable <option> Enable option <option>
-disable <option> Disable option <option>


Predefined optimization profile

  • For Debugging: "-opt 0". It is equivalent to "-pretty -disable inline -disable staticeval -disable share -debuginfo"
  • For Production: "-opt 3". It minimize the generated javascript by applying various optimizations until fix-point is reached

List of option to "-disable" or "-enable"

Option name Default Description
pretty false Pretty print the javascript output
debuginfo false Output debug information (location)
deadcode true Deadcode elimination
inline true Code inlining
shortvar true Shorten variable names
staticeval true Static evaluation of constants
share true Share string and number constants
strict true Enable strict mode
debugger true Keep debugger statements. Stripped otherwise
genprim true Generate dummy primitives when missing
excwrap true Wrap js exception into ocaml ones
optcall true Javascript optimizations