Rhetorical question: what does this do?

I think it's not obvious at a glance, so I created a truth table (1 = true, 0 = false):

And here's a simpler truth table with descriptions in English (notice how the rightmost column is identical to the previous table's rightmost column except here I'm using the words "yes" and "no" instead of 1 and 0):

All right, so .filter() should return false only when isProdBuild() && isScheduled() && !isNetlifyDeployPreview(). Like so:

.filter(
  (episode) => !(isProdBuild() && isScheduled(episode) && !isNetlifyDeployPreview())
)

Would that be easier to grasp? Or maybe move isScheduled() to the beginning so it's clearer that this filtering is about scheduled episodes:

.filter(
  (episode) => !(isScheduled(episode) && isProdBuild() && !isNetlifyDeployPreview())
)

Using one of De Morgan's laws – !(A && B) === !A || !B – the conditional could be flipped on its head:

.filter(
  (episode) => !isScheduled(episode) || !isProdBuild() || isNetlifyDeployPreview()
)

The conditional could be even easier to read if we created a new util isDevBuild():

.filter(
  (episode) => !isScheduled(episode) || isDevBuild() || isNetlifyDeployPreview()
)

Hmm, I take my words back – I think the conditional is clearer if isScheduled() is at the end:

.filter(
  (episode) => isDevBuild() || isNetlifyDeployPreview() || !isScheduled(episode)
)

Now it reads like English: "include all episodes in dev builds and Netlify deploy previews; otherwise include non-scheduled episodes." I think this would be the best option!

Which one is the best in your opinion?

• We already have a util called isNetlifyProdEnv(), so isNetlifyDeployPreview() would have a more consistent name.
• The check should be against process.env.CONTEXT, not process.env.NODE_ENV.
• With a similar JSDoc comment as in isNetlifyProdEnv(), the code could look like this:

I would also:

• Move this util to the beginning of the file so that all utils are sorted alphabetically.
• Simplify the JSDoc comment of isNetlifyProdEnv():

/**
 * Checks whether the current build is against Netlify's production.
 *
 * Returns `false` in non-Netlify environments, e.g. localhost.
 *
 * @see {@link https://docs.netlify.com/configure-builds/environment-variables/#build-metadata}
 *
 * @returns {boolean}
 */
export const isNetlifyProdEnv = () => process.env.CONTEXT === 'production'