mime.charsets in Response.js is undefined

[robertlario]

Using Express version 4.19.2 in Response.js at line 790 (var charset = mime.charsets.lookup(value.split(';')[0]);) is throwing an exception stating that mime.charset "TypeError: Cannot read properties of undefined (reading 'charsets')"

[wesleytodd]

Can you post some example code where it is having this error behavior?

[robertlario]

I am trying to run my code in serverless-offline.

I do not call the code directly.

Here is the stack trace:

TypeError: Cannot read properties of undefined (reading 'charsets')
at ServerResponse.header (..\node_modules\express\lib\response.js:790:1)
at ServerResponse.contentType (..\node_modules\express\lib\response.js:625:1)
at setContentTypeMiddleware (..\lib\router\middlewares\setContentType.js:15:1)
at Layer.handle [as handle_request] (..\node_modules\express\lib\router\layer.js:95:1)
at trim_prefix (..\node_modules\express\lib\router\index.js:328:1)
at ..\node_modules\express\lib\router\index.js:286:1
at Function.process_params (..\node_modules\express\lib\router\index.js:346:1)
at next (..\node_modules\express\lib\router\index.js:280:1)
at ..\lib\router\middlewares\setServerUrl.js:26:1
at .webpack\service\src\index.js:154906:9 {stack: 'TypeError: Cannot read properties of undefine…oyment.webpack\service\src\index.js:154906:9', message: 'Cannot read properties of undefined (reading 'charsets')'}

Here are my modules:
@types/cors@2.8.17
├── @types/errorhandler@0.0.32
├── @types/express-serve-static-core@4.17.43
├── @types/express@4.17.21
├── @types/flat@5.0.5
├── @types/http-errors@1.8.2
├── @types/jest@26.0.24
├── @types/lodash@4.14.202
├── @types/mime-types@2.1.4
├── @types/mock-req-res@1.1.6
├── @types/node@12.20.55
├── @types/uuid@3.4.13
├── @typescript-eslint/eslint-plugin@4.33.0
├── @typescript-eslint/parser@4.33.0
├── ajv-errors@1.0.1
├── ajv@6.12.6
├── aws-sdk-mock@5.9.0
├── aws-sdk@2.1573.0
├── aws-xray-sdk@3.5.4
├── cors@2.8.5
├── errorhandler@1.5.1
├── eslint-config-airbnb-base@14.2.1
├── eslint-config-prettier@8.10.0
├── eslint-plugin-import@2.29.1
├── eslint-plugin-prettier@4.2.1
├── eslint@7.32.0
├── express@4.19.2
├── flat@5.0.2
├── force@0.0.3
├── http-errors@1.8.1
├── jest-each@26.6.2
├── jest-mock-extended@1.0.18
├── jest@26.6.3
├── lodash@4.17.21
├── mime-types@2.1.35
├── mime@4.0.1
├── mock-req-res@1.2.1
├── prettier@2.8.8
├── serverless-http@2.7.0
├── sinon@10.0.1
├── standard-version@9.5.0
├── supertest@6.3.4
├── ts-jest@26.5.6
├── typescript@4.9.5
├── uuid@8.3.2

[wesleytodd]

I don't know what serverless offline is, but in the stack I see this is the closes thing that looks like user land code: at ..\lib\router\middlewares\setServerUrl.js:26:1

[robertlario]

at line 34 in response.js

var mime = send.mime;

send.mime appears to be undefined.

Any thoughts?

[wesleytodd]

https://github.com/pillarjs/send/blob/master/index.js#L71

I looked at that initially and am not sure how it could be. That is why I would need more to go off of to debug.

[wesleytodd]

Also, the npm ls output you showed doesn't show these things afaict. If you think it is something with the packages installed please post more of the output.

[robertlario]

It was a versioning issue! :-( What a nightmare!

Please consider the issue closed. Thank you for your help!

[wesleytodd]

Haha, no problem. Glad you got it sorted out!