update for types

packages/http-client/src/index.ts

@@ -275,9 +275,8 @@ export class HttpClient {
       Headers.Accept,
       MediaTypes.ApplicationJson
     )
-    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultHeader(
+    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultContentTypeHeader(
       additionalHeaders,
-      Headers.ContentType,
       MediaTypes.ApplicationJson
     )
     const res: HttpClientResponse = await this.post(
@@ -299,9 +298,8 @@ export class HttpClient {
       Headers.Accept,
       MediaTypes.ApplicationJson
     )
-    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultHeader(
+    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultContentTypeHeader(
       additionalHeaders,
-      Headers.ContentType,
       MediaTypes.ApplicationJson
     )
     const res: HttpClientResponse = await this.put(
@@ -323,9 +321,8 @@ export class HttpClient {
       Headers.Accept,
       MediaTypes.ApplicationJson
     )
-    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultHeader(
+    additionalHeaders[Headers.ContentType] = this._getExistingOrDefaultContentTypeHeader(
       additionalHeaders,
-      Headers.ContentType,
       MediaTypes.ApplicationJson
     )
     const res: HttpClientResponse = await this.patch(
@@ -632,12 +629,64 @@ export class HttpClient {
     additionalHeaders: http.OutgoingHttpHeaders,
     header: string,
     _default: string
-  ): string | number | string[] {
+  ): string | string[] {
+    let clientHeader: string | string[] | undefined
+    if (this.requestOptions && this.requestOptions.headers) {
+      const headerValue = lowercaseKeys(this.requestOptions.headers)[header]
+      if (headerValue) {
+        clientHeader = typeof headerValue === 'number' ? headerValue.toString() : headerValue
+      }
+    }
+    
+    const additionalValue = additionalHeaders[header]
+    
+    if (additionalValue !== undefined) {
+      return typeof additionalValue === 'number' ? additionalValue.toString() : additionalValue
+    }
+    
+    if (clientHeader !== undefined) {
+      return clientHeader
+    }
+    
+    return _default
+  }
+  
+  private _getExistingOrDefaultContentTypeHeader(
+    additionalHeaders: http.OutgoingHttpHeaders,
+    _default: string
+  ): string {
     let clientHeader: string | undefined
     if (this.requestOptions && this.requestOptions.headers) {
-      clientHeader = lowercaseKeys(this.requestOptions.headers)[header]
+      const headerValue = lowercaseKeys(this.requestOptions.headers)[Headers.ContentType]
+      if (headerValue) {
+        if (typeof headerValue === 'number') {
+          clientHeader = String(headerValue)
+        } else if (Array.isArray(headerValue)) {
+          clientHeader = headerValue.join(', ')
+        } else {
+          clientHeader = headerValue
+        }
+      }
     }
-    return additionalHeaders[header] || clientHeader || _default
+    
+    const additionalValue = additionalHeaders[Headers.ContentType]
+    
+    // Return the first non-undefined value, converting numbers or arrays to strings if necessary
+    if (additionalValue !== undefined) {
+      if (typeof additionalValue === 'number') {
+        return String(additionalValue)
+      } else if (Array.isArray(additionalValue)) {
+        return additionalValue.join(', ')
+      } else {
+        return additionalValue
+      }
+    }
+    
+    if (clientHeader !== undefined) {
+      return clientHeader
+    }
+    
+    return _default
   }
 
   private _getAgent(parsedUrl: URL): http.Agent {