msgpack-lite/lib/ext.js

// ext-codec.js

exports.Ext = Ext;

var ExtBuffer = require("./ext-buffer").ExtBuffer;

function Ext() {
  if (!(this instanceof Ext)) return new Ext();
  this.extPackers = {};
  this.extUnpackers = [];
}

Ext.prototype.addExtPacker = function(etype, Class, packer) {
  var name = Class.name;
  if (name && name !== "Object") {
    this.extPackers[name] = extPacker;
  } else {
    var list = this.extEncoderList || (this.extEncoderList = []);
    list.unshift([Class, extPacker]);
  }

  function extPacker(value) {
    var buffer = packer(value);
    return new ExtBuffer(buffer, etype);
  }
};

Ext.prototype.addExtUnpacker = function(etype, unpacker) {
  this.extUnpackers[etype] = unpacker;
};

Ext.prototype.getExtPacker = function(value) {
  var c = value.constructor;
  var e = c && c.name && this.extPackers[c.name];
  if (e) return e;
  var list = this.extEncoderList;
  if (!list) return;
  var len = list.length;
  for (var i = 0; i < len; i++) {
    var pair = list[i];
    if (c === pair[0]) return pair[1];
  }
};

Ext.prototype.getExtUnpacker = function(type) {
  return this.extUnpackers[type] || extUnpacker;

  function extUnpacker(buffer) {
    return new ExtBuffer(buffer, type);
  }
};