jade's buffer technique (exclamation mark)

Question

In github's jade documentation, it talks about the buffered technique:

Code buffered by = is escaped by default for security, however to output unescaped return values you may use !=:

p!= aVarContainingMoreHTML

I don't quite understand the use of exclamation mark here, I mean, why not just use:

p= aVarContainingMoreHTML

In fact, I don't quite understand the usage of the buffer technique, there isn't much related to it in the doc

Answer 1

Without the !, p= aVarContainingMoreHTML would render brackets as > and &lt whereas p!= aVarContainingMoreHTML would render the var as HTML. You should only use ! when you really need to.