Is noop a pure function?

Asked Jan 23 '20 at 22:18

Active Jan 23 '20 at 22:18

Viewed 71 times

In JavaScript, we can express a simple noop function like so (It's the same in Lodash):

const noop = () => {};

It might be a frivolous distinction, but does it count as a pure function? My initial guess was that it is because:

Referentially transparent because it always returns undefined.
Doesn't cause any side effect.

But if we invoke this function repeatedly (like the code block below that assigns undefined to a bunch of variables), wouldn't it eventually cause a different behavior (like crashing the program) because the external state has been changing all along?

const a = noop();
const b = noop();
const c = noop();
const d = noop();
...
...
(... until memory runs out)

(Or should we just leave aside the question of memory, etc. in this context?)

asked Jan 23 '20 at 22:18

sshh

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By the definition you're trying to use there, I don't think any function would be considered pure. – John Montgomery Jan 23 '20 at 22:21
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noop() isn't changing the state, creating ```a``` or ```b``` or any variable at all is what is changing the state. – Michael Bianconi Jan 23 '20 at 22:22
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When talking about "pure functions", we enter a theoretical realm where memory is no longer limited. – Code-Apprentice Jan 23 '20 at 22:22
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Relevant: https://stackoverflow.com/q/58744557/251311 – zerkms Jan 23 '20 at 22:36

Is noop a pure function?

0 Answers0