Understanding routing is essential to extend our back end code. We are going to play through some simple routing examples.
In general, routing stands for how an application responds to specific endpoints and methods.
In Express.js, one path can respond to different HTTP methods and can have multiple handler functions. These handler functions are executed one by one in the order they were specified in the code. A path can be a simple string, but also a complex regular expression or pattern.
When using multiple handler functions—either provided as an array or multiple parameters—be sure to pass next to every callback function. When you call next, you hand over the execution from one callback function to the next function in the row. Those functions can also be middleware. We'll cover this in the next section.
Here is a simple example. Replace...