I really like React, but I have to admit, that I don&#x27;t write big apps with it (yet).<p>There is one thing though which I find results in subtil bugs (entirely my fault): When one input is changing and depending on that input another output value has to change than the input shouldn&#x27;t change state yet and the output should be computed from input (+ state where necessary). Only then you should set the state.<p>Do not set the state before computing the output and don&#x27;t compute the output from the previous state only. This will result in subtle and sometimes hard-to-find bugs.