Build error

[holtzermann17]

After cd crdt, yarn, yarn build I get:

Version: webpack 3.12.0
Time: 1865ms
    Asset    Size  Chunks                    Chunk Names
bundle.js  911 kB       0  [emitted]  [big]  main
   [6] ./stores/document.js 161 bytes {0} [built]
 [100] multi ./index.js 28 bytes {0} [built]
 [101] ./index.js 1.05 kB {0} [built]
 [112] ./api/index.js 458 bytes {0} [built]
 [113] ./api/apply_operations.js 365 bytes {0} [built]
 [114] ./api/get_document_text.js 257 bytes {0} [built]
 [115] ./api/get_document_operations.js 270 bytes {0} [built]
 [116] ./api/replicate_document.js 279 bytes {0} [built]
 [117] ./api/set_document.js 235 bytes {0} [built]
 [118] ./api/set_text_in_range.js 344 bytes {0} [built]
 [119] ./io/index.js 590 bytes {0} [built]
 [120] ./utils/logger.js 492 bytes {0} [built]
 [136] ./node_modules/logform ^\.\/.*\.js$ 1.12 kB {0} [built]
 [138] ./node_modules/logform/dist ^\.\/.*\.js$ 508 bytes {0} [built]
    + 189 hidden modules

ERROR in ./node_modules/winston/lib/winston/transports/http.js
Module parse failed: Unexpected token (186:6)
You may need an appropriate loader to handle this file type.
|     }
|     const req = (this.ssl ? https : http).request({
|       ...this.options,
|       method: 'POST',
|       host: this.host,
 @ ./node_modules/winston/lib/winston/transports/index.js 42:11-28
 @ ./node_modules/winston/lib/winston.js
 @ ./utils/logger.js
 @ ./index.js
 @ multi ./index.js
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.