[fix] `encoding` is still required in TS even though it has default value from `co-body`

[Jerome De Leon]

Describe the bug

Node.js version: 18.6.1
OS version: macOS 12.6

Description: When I used the v5 of this lib, I am getting a type error from the encoding field being required but the README.md says that it has a default value suggesting it isn't required.

bodyparser/README.md

Line 50 in 664cd7c

 - **encoding**: requested encoding. Default is `utf-8` by `co-body`. 

Another thing is that encoding is not being passed on to the co-body's parse function so it seems useless compared to v4 where it uses copy-to's copy function to merge options.

bodyparser/index.js

Lines 50 to 111 in 5678a79

   const jsonOpts = formatOptions(opts, 'json'); 
   const formOpts = formatOptions(opts, 'form'); 
   const textOpts = formatOptions(opts, 'text'); 
   const xmlOpts = formatOptions(opts, 'xml'); 
  
   const extendTypes = opts.extendTypes || {}; 
  
   extendType(jsonTypes, extendTypes.json); 
   extendType(formTypes, extendTypes.form); 
   extendType(textTypes, extendTypes.text); 
   extendType(xmlTypes, extendTypes.xml); 
  
   // eslint-disable-next-line func-names 
   return async function bodyParser(ctx, next) { 
     if (ctx.request.body !== undefined || ctx.disableBodyParser) 
       return await next(); // eslint-disable-line no-return-await 
     try { 
       const res = await parseBody(ctx); 
       ctx.request.body = 'parsed' in res ? res.parsed : {}; 
       if (ctx.request.rawBody === undefined) ctx.request.rawBody = res.raw; 
     } catch (err) { 
       if (onerror) { 
         onerror(err, ctx); 
       } else { 
         throw err; 
       } 
     } 
  
     await next(); 
   }; 
  
   async function parseBody(ctx) { 
     if ( 
       enableJson && 
       ((detectJSON && detectJSON(ctx)) || 
         isTypes(ctx.request.get('content-type'), jsonTypes)) 
     ) { 
       return await parse.json(ctx, jsonOpts); // eslint-disable-line no-return-await 
     } 
  
     if (enableForm && ctx.request.is(formTypes)) { 
       return await parse.form(ctx, formOpts); // eslint-disable-line no-return-await 
     } 
  
     if (enableText && ctx.request.is(textTypes)) { 
       return (await parse.text(ctx, textOpts)) || ''; 
     } 
  
     if (enableXml && ctx.request.is(xmlTypes)) { 
       return (await parse.text(ctx, xmlOpts)) || ''; 
     } 
  
     return {}; 
   } 
 }; 
  
 function formatOptions(opts, type) { 
   const res = {}; 
   copy(opts).to(res); 
   res.limit = opts[type + 'Limit']; 
   return res; 
 } 

compared to v5 where it limits the options

bodyparser/src/body-parser.ts

Lines 63 to 73 in 664cd7c

 const parserOptions = { 
   // force co-body return raw body 
   returnRawBody: true, 
   strict: bodyType === 'json' ? restOpts.jsonStrict : undefined, 
   [`${bodyType}Types`]: mimeTypes[bodyType], 
   limit: restOpts[`${shouldParseBodyAs('xml') ? 'xml' : bodyType}Limit`], 
 }; 
  
 return parser[bodyType](ctx, parserOptions) as Promise< 
   Record<string, string> 
 >; 

so I'm not entirely sure if we should document this as breaking changes that we're not able to override the encoding or any other values or fix this type of issue.

Also, I think it's an issue with co-body type declaration where they explicitly put undefined as part of the type telling us to explicitly pass a value of undefined

https://github.com/DefinitelyTyped/DefinitelyTyped/blob/def5996adb3596c8c468922ed0ac55110cd47fcc/types/co-body/index.d.ts#L33-L42

Actual behavior

Argument of type '{ jsonLimit: string; }' is not assignable to parameter of type 'BodyParserOptions'.
  Property 'encoding' is missing in type '{ jsonLimit: string; }' but required in type 'Pick<Options, "encoding">'.ts(2345)

Expected behavior

Should not be getting any type of error

Code to reproduce

For whatever reason, I wasn't able to replicate it in the TS playground but I was able to replicate it in CodeSandbox.

Workaround

bodyParser({ ...yourOptions, encoding: undefined }) // only if you're not overriding it

Checklist

• I have searched through GitHub issues for similar issues.
• I have completely read through the README and documentation.
• I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.

[Imed Jaberi]

Thanks @JeromeDeLeon for your catch! Yup, it looks like an issue with the co-body, and from our side we don't pass the encoding option ... I am working on it and expect the new release soon!