Branching.
WHAT A CONDITION DOES
Runs code only when something is true.
THE STRUCTURE
If, optionally followed by alternatives, optionally followed by a fallback.
WHAT COUNTS AS TRUE
Non-zero numbers, non-empty text and non-empty collections are treated as true.
Zero, empty values and the absence of a value are treated as false.
WHY THAT MATTERS
It allows concise checks, and it causes confusion when a value could legitimately be zero.
THAT CASE
Check explicitly for the absence of a value rather than relying on truthiness, where zero is valid.
COMPARISONS
Equality, inequality, and ordering.
Note that equality and identity are different checks.
COMBINING CONDITIONS
With and, or, and not.
Keep them readable. A condition needing careful reading should be split.
WHAT TO AVOID
Deeply nested conditions Repeating the same check in several places Conditions with side effects
WHAT TO PREFER
Returning early rather than nesting deeply.
