As architects, we'll start a project with a lengthy list of requirements from the client that need to be implemented for them to be satisfied. There'll be explicit things such as "login feature" and "mobile friendly", but there are requirements that are not included in this list that nonetheless are unavoidable requirements for every client.
One of these is that the application should perform well. This is a catchall term that could include:
Responsiveness of UI elements
Initial application start up time
Remote requests such as load/save
A slow application is a key source of user frustration and the first step to diagnosing any issues of this nature is to collect information.
Let's look at the various ways in which Chrome Developer Tools can help us and address common problems using Ext JS.