Parse a json encoded hashmap or return an empty one and print a warning

parse_msg.coffee

# Parse a json encoded hashmap or return an empty one and print a warning

parseMsg = (jsonStr) ->
  try json = JSON.parse jsonStr
  catch err then handleParseErr err, jsonStr
  json ? {}

handleParseErr = (err, jsonStr) ->
  console.error '[WARN]','JSON parser:', err, 'input json was:', jsonStr

if process.argv[1] is __filename

  assert = require 'assert'

  assert.deepEqual (parseMsg '{'),         {}
  assert.deepEqual (parseMsg 'daskh das'), {}

  assert.deepEqual (parseMsg '{ "foo": 1 }'), { foo: 1 }