When using inheritance and blocks, sometimes we want to add to the content instead of overwriting it. We can do so with the "append" and "prepend" keywords. Either by itself along with the block name, or as a parameter to the "block" keyword.
Example: if we have the parent template base.jade:
// base.jade h1 Hello from the base block content p Welcome
And we want our child to append to the content block:
// child.jade extends base block append content p And goodbye
This will output:
<h1>Hello from the base</h1> <p>Welcome</p> <p>And goodbye</p>
As mentioned you can skip the block keyword and just use append or prepend.
// child.jade extends base append content p And goodbye