Referential transparency is a property of a function that allows it to be replaced by its equivalent output. In simpler terms, if you call the function a second time with the same arguments, you’re guaranteed to get the same returning value.

Pure functions are always referentially transparent.

“Referential transparency” is a fancy way of saying that a function call can be replaced by its would-be return value because it’s the same every time. Referentially transparent functions can be safely memoized memoization.

The great thing about pure functions is that they can always be safely memoized. Impure functions can’t be because they might do something in addition to returning a static value, or they might return different values given the same arguments.

References

• https://www.baeldung.com/cs/referential-transparency#referential-transparency
• boot.dev

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