What s the difference between pure and impure pipes

Question

Can you explain with an example that What’s the difference between pure and impure pipes?

Answer 1

Aspect	Pure Pipes	Impure Pipes
Definition	Pipes that execute only when the input value or parameters change.	Pipes that execute on every change detection cycle, regardless of input changes.
Performance	More efficient, as they run less frequently.	Less efficient, as they run frequently.
Usage	Default behavior for pipes.	Explicitly marked as impure in the @Pipe decorator.
Change Detection	Runs only when the input is a primitive value or the object reference changes.	Runs on every change detection cycle, even if the input or parameters haven’t changed.
Use Case	Ideal for transformations that depend only on input values (e.g., formatting dates, numbers).	Useful for transformations that depend on internal state or complex logic (e.g., filtering arrays).