erlang-bindings

Erlang Bindings for Node.js

Call functions on a remote Erlang node from JavaScript.

Requires Erlang development headers, usually included in a typical Erlang client installation.

Usage

See test-napi.js for a more complete list of examples

If you spawn a node in Erlang called remotenode@127.0.0.1 with cookie "mycookie", you can connect to it in Node.js with the following code

const {ErlangNode,tuple,charlist} = require('erlang-bindings');
// will be accessible on the Erlang server as 'mynodename@127.0.0.1'
const mynode = new ErlangNode("mynodename", "mycookie", "remotenode@127.0.0.1");
mynode.on('message', function(data) {
  // contains a message from the remote node
});
mynode.on('tick', function() {
  // the remote node is checking this node's health, no need to do anything
});
mynode.on('error', function(errorNumber) {
  // something bad happened
});
// do something
mynode.disconnect();

You can run remote calls using member function rpc(module, function name, arg1, ...)

console.log(mynode.rpc('erlang', 'max', 3, 8)) // 8

And you can send data to the NodeJS node in Elixir like so

send {:'mynodename', :'mynodename@127.0.0.1'}, "HELLO"
send {:'mynodename', :'mynodename@127.0.0.1'}, [1,2,3]

Tuples

Tuples can be sent by using the tuple() function

const {tuple} = require('erlang-bindings');
console.log(mynode.rpc('erlang', 'tuple_size', tuple(5,2,"hello"))) // 3

Atoms

const {atom} = require('erlang-bindings');
console.log(mynode.rpc('erlang', 'atom_to_list', atom('hello'))) // 'hello'

Charlists

To represent a charlist in JavaScript, use charlist(str) from the package, which will convert your string into an array of character points. Only works for ASCII.

const {charlist} = require('erlang-bindings');
console.log(charlist("ABC")); // [65,66,67]

Maps

JavaScript objects are automatically converted into erlang maps

JavaScript: {a: 3} Erlang: %{'a' => 3}

If you need atoms for keys, use the atom function:

JavaScript: const map = {}; map[atom('a')] = 3 Erlang: %{a: 3}

Elixir

Remote connections to Elixir nodes offer conva special provisioning allowing RPC calls to modules under the Elixir module to be written as if they were native Node.js function calls.

node.ex.String.split("1864-05-23","-")
// is identical to
node.rpc("Elixir.String", "split", "1864-05-23", "-")