toLowerCase of undefined about negotiator

[dougwilson]

Would you be able to post a standard-formatted stack trace or code to reproduce? Either of those two would help a lot :)

[NoumanSaleem]

@dougwilson wish I had some more context around this. Unfortunately just have the error itself. I'll be doing some more digging into reproducing this. Hope the slightly better (maybe not) formatting helps :)

It happened in an express web application (express v4.8.7)

thanks!

trace=[
    column=54,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=null,
    line=81,
    method=null,
    native=false,
    column=null,
    file=null,
    function=Array.every,
    line=null,
    method=every,
    native=true,
    column=14,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=specify,
    line=80,
    method=null,
    native=false,
    column=12,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=accepted.map.filter.sort.s,
    line=48,
    method=map.filter.sort.s,
    native=false,
    column=null,
    file=null,
    function=Array.map,
    line=null,
    method=map,
    native=true,
    column=20,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=getMediaTypePriority,
    line=47,
    method=null,
    native=false,
    column=21,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=provided.map.filter.sort.pa,
    line=101,
    method=map.filter.sort.pa,
    native=false,
    column=null,
    file=null,
    function=Array.map,
    line=null,
    method=map,
    native=true,
    column=21,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js,
    function=preferredMediaTypes,
    line=100,
    method=null,
    native=false,
    column=12,
    file=/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/negotiator.js,
    function=Negotiator.(anonymousfunction),
    line=26,
    method=(anonymousfunction),
    native=false
],
stack=[
    TypeError: Cannotcallmethod'toLowerCase'ofundefined,
    at/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 81: 54,
    atArray.every(native),
    atspecify(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 80: 14),
    ataccepted.map.filter.sort.s(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 48: 12),
    atArray.map(native),
    atgetMediaTypePriority(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 47: 20),
    atprovided.map.filter.sort.pa(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 101: 21),
    atArray.map(native),
    atpreferredMediaTypes(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/mediaType.js: 100: 21),
    atNegotiator.(anonymousfunction)(/app/node_modules/express/node_modules/accepts/node_modules/negotiator/lib/negotiator.js: 26: 12)
]

[dougwilson]

I think this error is because you are adding an enumerable property on Object.prototype, which will wreck havoc in all sorts of weird places. Would you be willing to show the output of the following within your application's code?

console.dir(Object.prototype)

[dougwilson]

Nevermind, I have determined the cause and it's from an invalid media type most likely. Example: text/html; foo (foo at the end is invalid because it needs to be a key value pair).

[dougwilson]

OK, so what I believe was causing your issue should be resolved now. I'll issue out a new version of this module and accepts module and you should be able to npm update your express install to pull it in.

[NoumanSaleem]

@dougwilson really appreciate the quick response on this and your work on express!

[dougwilson]

You're welcome :) And let me know if you're still seeing this error pop up, even after updating accepts to 1.1.2, since I fixed a error with the same stack trace you provided, but cannot be 100% sure it fixed your issue :)