Fix path detection can crash app (if req.originalUrl is not set)

[iamjochem]

hi there,

Background

the following line crashes if req.originalUrl is not set (it is technically possible even though unexpected in the context of express!):

i18next-express-middleware/src/languageLookups/path.js

Line 16 in 095a5a9

let parts = req.originalUrl.split('/');

having encountered that I decided to try and set the lookupFromPathIndex option to undefined, but that is not possible due to the default value being 0 in combination with how the option defaults are applied (undefined values are always overwritten) i.e.

setting of option defaults happens here:

i18next-express-middleware/src/LanguageDetector.js

Line 33 in 095a5a9

this.options = utils.defaults(options, this.options || {}, getDefaults());

logic for merging options with defaults is here: https://github.com/i18next/i18next-express-middleware
/blob/095a5a926a2ad9e6dcaebc2a22cbb42780b4003e/src/utils.js#L26

"Solution"

this PR :-) the changes are as follows:

1. change the type check of lookupFromPathIndex so the "by index" lookup is only attempted if the value is a number - this allows people to turn it off by setting the option to false
2. add a check for existence of req.originalUrl - to avoid potential TypeErrors
3. add a check for existence of req.params - to avoid potential TypeErrors (because I'm paranoid)

number 3 in the list is not directly related to the issue I had but I figured "better safe than sorry"

[jamuhl]

LookupFromPath can be disabled by not having it in the lookups array: https://github.com/i18next/i18next-express-middleware#detector-options so that options does only set where to look it up...not if on or off

but anyway...the changes do not hurt at all ;)

thank you...merging and publishing

[jamuhl]

i18next-express-middleware@1.0.7

[iamjochem]

boy that was fast! thanks.