fix: prevent undefined from getting stringified

Author: Daniel Bot

src/openapi-lambda-adapters.test.ts

@@ -150,11 +150,13 @@ describe('Adapt axios request/response to AWS Lambda Proxy Event/Response', () =
         headers: {
           'x-boolean': true,
           'x-number': 100,
+          'x-zero': 0,
           'x-object': {
             key: 'value'
           },
           'x-array': ['a', 'b'],
           'x-null': null,
+          'x-undefined': undefined,
           'x-string': 'string'
         } as unknown as Record<string, string>
       }
@@ -169,10 +171,12 @@ describe('Adapt axios request/response to AWS Lambda Proxy Event/Response', () =
 
       expect(event.headers['x-boolean']).toBe('true')
       expect(event.headers['x-number']).toBe('100')
+      expect(event.headers['x-zero']).toBe('0')
       expect(event.headers['x-string']).toBe('string')
       expect(event.headers['x-object']).toBe('[object Object]')
       expect(event.headers['x-array']).toBe('a,b')
       expect(event.headers['x-null']).toBeUndefined()
+      expect(event.headers['x-undefined']).toBeUndefined()
     })
   })
 

src/openapi-lambda-adapters.ts

@@ -54,7 +54,7 @@ export const convertAxiosToApiGw = (config: AxiosRequestConfig, operation: Opera
   Object.entries(config.params ?? {}).forEach(([key, val]) => urlSearchParams.append(key, val.toString()))
 
   const headers: Record<string, string> = {}
-  for (const [key, val] of Object.entries(config.headers ?? {}).filter(([_key, val]) => val !== null)) {
+  for (const [key, val] of Object.entries(config.headers ?? {}).filter(([_key, val]) => val !== null && val !== undefined)) {
     headers[key] = val.toString()
   }