fix: ignore error caused by Cloudflare HTML response (#6356)

* fix: ignore error caused by Cloudflare HTML response

* add test

* Update src/tracing/errors.test.ts
Co-authored-by: Zach Pomerantz <zzmp@uniswap.org>

* Update src/tracing/errors.ts
Co-authored-by: Zach Pomerantz <zzmp@uniswap.org>

* Update src/tracing/errors.ts
Co-authored-by: Zach Pomerantz <zzmp@uniswap.org>

* multiline

src/tracing/errors.test.ts

@@ -24,4 +24,9 @@ describe('filterKnownErrors', () => {
     const originalException = new Error('user rejected transaction')
     expect(filterKnownErrors(ERROR, { originalException })).toBe(null)
   })
+
+  it('filters invalid HTML response errors', () => {
+    const originalException = new SyntaxError("Unexpected token '<'")
+    expect(filterKnownErrors(ERROR, { originalException })).toBe(null)
+  })
 })

src/tracing/errors.ts

@@ -25,6 +25,13 @@ export const filterKnownErrors: Required<ClientOptions>['beforeSend'] = (event:
 
     // If the error is based on a user rejecting, it should not be considered an exception.
     if (didUserReject(error)) return null
+
+    /*
+     * This is caused by HTML being returned for a chunk from Cloudflare.
+     * Usually, it's the result of a 499 exception right before it, which should be handled.
+     * Therefore, this can be ignored.
+     */
+    if (error.message.match(/Unexpected token '<'/)) return null
   }
 
   return event