When first call encounter exception, the function always return exception

[zacyang]

Notice the cache did not distinguish error from regular return, meaning if first try failed, all the subsequent call will fai.
Can we add a configure to allow only cache the success return?

[fregante]

The result of functions isn't stored if they throw errors, but rejected promises are indeed stored. What you're asking is covered by p-memoize, which is a mem wrapper

https://github.com/sindresorhus/p-memoize#cachepromiserejection