Error when building Wasm on OSX

[johannbarbie]

i went through similar instructions on High Sierra:

brew install opam ocaml
opam init -y
eval $(opam config env)
opam install cryptokit yojson

Then encountered this error when executing make to build wasm:

# Error: This expression has type bytes but an expression was expected of type
#          string

[johannbarbie]

looked up the error here: facebook/flow#5270

export OCAMLPARAM="safe-string=0,_"

solved the issue, all tests passing.

[mrsmkl]

Hopefully this is fixed in #97

[mrsmkl]

I guess this has now been fixed, we use a later version of OCaml now