Error
TypeError: Cannot read property 'length' of undefined
   at Object.render (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/components/Categories.js:85:34)
   at /home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:793:21
   at measureLifeCyclePerf (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:73:12)
   at ReactCompositeComponentWrapper._renderValidatedComponentWithoutOwnerOrContext (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:792:25)
   at ReactCompositeComponentWrapper._renderValidatedComponent (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:819:32)
   at ReactCompositeComponentWrapper.performInitialMount (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:359:30)
   at ReactCompositeComponentWrapper.mountComponent (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:255:21)
   at Object.mountComponent (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactReconciler.js:43:35)
   at ReactCompositeComponentWrapper.performInitialMount (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:368:34)
   at ReactCompositeComponentWrapper.mountComponent (/home/bolej/domains/fazanavard.com/public_html/shopwebsite/client/node_modules/react-dom/lib/ReactCompositeComponent.js:255:21)