demo error

[nlefebvre1410]

hi,
error npm start to :

internal/streams/legacy.js:59
      throw er; // Unhandled stream error in pipe.
      ^
Error: ./pub/client/src/app.js
Module build failed: ReferenceError: [BABEL] /Users/nicolaslefebvre/Downloads/generate-pdf-master/pub/client/src/app.js: Unknown option: /Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/react/react.js.Children. Check out http://babeljs.io/docs/usage/options/ for more information about options.

A common cause of this error is the presence of a configuration options object without the corresponding preset name. Example:

Invalid:
  `{ presets: [{option: value}] }`
Valid:
  `{ presets: [['presetName', {option: value}]] }`

For more detailed information on preset configuration, please see http://babeljs.io/docs/plugins/#pluginpresets-options. (While processing preset: "/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/react/react.js")
    at Logger.error (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/logger.js:41:11)
    at OptionManager.mergeOptions (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:226:20)
    at /Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:265:14
    at /Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:323:22
    at Array.map (native)
    at OptionManager.resolvePresets (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:275:20)
    at OptionManager.mergePresets (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:264:10)
    at OptionManager.mergeOptions (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:249:14)
    at OptionManager.init (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/options/option-manager.js:368:12)
    at File.initOptions (/Users/nicolaslefebvre/Downloads/generate-pdf-master/node_modules/babel-core/lib/transformation/file/index.js:212:65)
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