fix(pwa-utils): handle non-strings in startCase

[alexkcollier]

adding a route to workbox.runtimeCaching results in

✖ Nuxt Fatal Error                                 
│                                                      
│   TypeError: Cannot read property '0' of undefined 

if its handler is undefined

[codecov]

Codecov Report

Merging #150 into dev will not change coverage.
The diff coverage is n/a.

@@         Coverage Diff         @@
##            dev   #150   +/-   ##
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  Coverage   100%   100%           
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  Files         1      1           
  Lines         2      2           
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  Hits          2      2

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[pi0]

Thanks. But what's the use case of passing undefined as a handler? Would you please add an example to the fixture if there is?

[manniL]

@pi0 discovered the same issue rn 🙈 Not specifying a handler should/will default to "networkFirst"

(at least that is what the documentation says: https://pwa.nuxtjs.org/modules/workbox.html#examples)

[alexkcollier]

@pi0 in the line below, undefined always gets passed to startCase() if a handler is omitted (i.e.: { urlPattern: 'someurl' }), which throws an error with the way the function was written

pwa-module/packages/workbox/lib/options.js

Line 78 in 782217a

handler: startCase(entry.handler) || 'NetworkFirst',

Changing the line to handler: entry.handler ? startCase(entry.handler) : 'NetworkFirst' would solve this as well.

[pi0]

Thanks @manniL @alexkcollier