`TypeError: string is not a function` in mo.jo/.../heartbeater.js

[trentm]

{
  "error": "error getting tree '528e0dfc0dd39ddf4e90abd30e8a86379e065c9e'",
  "details": {
    "stack": "TypeError: string is not a function\\n at String.CALL_NON_FUNCTION_AS_CONSTRUCTOR (native)\\n at [object Object].unpack_object (/home/jill/molybdenum/node_modules/trentm-git/lib/git/pack_storage.js:111:11)\\n at [object Object].unpack_deltified (/home/jill/molybdenum/node_modules/trentm-git/lib/git/pack_storage.js:140:27)\\n at [object Object].unpack_object (/home/jill/molybdenum/node_modules/trentm-git/lib/git/pack_storage.js:106:17)\\n at [object Object].parse_object (/home/jill/molybdenum/node_modules/trentm-git/lib/git/pack_storage.js:67:21)\\n at [object Object].find (/home/jill/molybdenum/node_modules/trentm-git/lib/git/pack_storage.js:55:18)\\n at /home/jill/molybdenum/node_modules/trentm-git/lib/git/repository.js:178:22\\n at [object Object].get_object_by_sha1 (/home/jill/molybdenum/node_modules/trentm-git/lib/git/repository.js:187:11)\\n at [object Object].cat_file (/home/jill/molybdenum/node_modules/trentm-git/lib/git/repository.js:209:15)\\n at [object Object].cat_file (/home/jill/molybdenum/node_modules/trentm-git/lib/git/git.js:434:36)",
    "arguments": [
      "string"
    ],
    "type": "called_non_callable",
    "message": "string is not a function"
  }
}

https://mo.joyent.com/cnapi/blob/master/lib/heartbeater.js

[trentm]

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