The interview was taken by the Director of Engineering Samba Potla. The questions had to be coded on codesandbox. At first, he asked me to create an analog clock in ReactJS on a sandbox. I wrote the logic but could not complete the task. He then asked to explain why keys in ReactJS are necessary with an example in the code. I tried to create an example using sorting a list and updating it but the example did not work. The interview finished and I knew what my feedback would be. After the interview I created an analog clock https://codesandbox.io/s/vigorous-bash-9zdco React Keys Demo http://jsbin.com/wohima/edit?js,output