faker.lorem.word can return undefined despite being typed as string

[justinsmid]

Describe the bug

When calling faker.lorem.word with a length that doesn't have any matching words, it will return undefined while TypeScript thinks it's a string.

Reproduction

const nonexistentWord = faker.lorem.word(9999) // <-- typed as `string`
console.log(nonexistentWord) // <-- will output `undefined`

Additional Info

No response

[ST-DDT]

What is your expected behavior?

• Getting a word with a different length
• or always being forced to handle possibly undefined values
• or throwing/catching an exception?

EDIT: We could introduce two signatures for those methods though. One without length and a guaranteed string and one with length and string?.

[justinsmid]

I think i would personally expect it to be typed as string | undefined.

Getting a word with a different length when explicitly specifying a length seems like it'd be more troublesome, and having a function suddenly able to throw errors while other faker functions don't do so doesn't seem like a good idea either imo.

Splitting it up into separate methods like you suggested seems reasonable.

EDIT: Alternatively, we could use conditional types to return either string or string | undefined depending on whether a length was given. Something like this.

[MasterOdin]

Could the function be made such that if you pass in a length that's greater than any word, it caps the value to the max word length? The few times I've used this function in the past, it was being passed into a function or whatever that doesn't allow undefined, and adding as string to every usage would be pretty annoying. Why would someone want this function to return undefined?

[ST-DDT]

What about shorter words e.g. length = 1?

[MasterOdin]

length <= 0 also returns undefined for all locales, but I'd argue there to just return '' in those cases since. For length = 1, this only affects the hebrew locale, and there, maybe just bump it up to the next possible length (2)?

[hankucz]

In #1218 I implemented it in a way that if a user expects too long word, the maximum possible length is given.

[ST-DDT]

Team decision

• Throw an error by default, introduce options param that can be used to configure the errorHandling (e.g. return closest length).

Further discussions

• Introduce min and max length range in a separate PR. word(number| {min: length, max: length, length, errorHandling})

[ST-DDT]

Note since we need this in multiple modules this should be done in a new central method: faker.helpers.stringArrayElement(elements, options)

[ST-DDT]

Note2 it should be applies/used for all of our word methods (those with a length parameters) in a single PR.

[Shinigami92]

Just to raise my voice because I suffer in silence: I would suggest to name it strategy instead of errorHandling

[ST-DDT]

OK.

strategy: 'fail' | 'return-any' = 'fail'

Or fail-if-unavailable? Or throw-if-unavailable?

[import-brain]

OK.

strategy: 'fail' | 'return-any' = 'fail'

Or fail-if-unavailable? Or throw-if-unavailable?

What about just throw?