Getting Change Events don't return the field changed_fields anymore since version 20.0.0

[denizelderenbos]

change_event.changed_fields becomes undefined after upgrading google-ads-api past v19.0.2

Description

When querying the Google Ads API for change_event records, prior to v19.0.2 the changed_fields field was returned as an object with a paths array:

{
  // … other fields …
  "changed_fields": {
    "paths": [
      "amount_micros"
    ]
  }
}

But as soon as we upgrade to v20.0.0 (and later), the same query returns:

{
  // … other fields …
  "changed_fields": undefined
}

This appears to be a breaking change in the wrapper’s parsing logic, since the raw REST response still includes the changed_fields payload when inspected via curl or a proxy.

Steps to Reproduce

1. Pin your project to google-ads-api@20.0.0 and execute:

   const result = await customer.query(`
     SELECT
       change_event.change_date_time,
       change_event.change_resource_name,
       change_event.changed_fields
     FROM change_event
     WHERE change_event.change_date_time DURING TODAY
     LIMIT 1
   `)
   console.log(result[0].changed_fields)
   // → { paths: ["..."] }
   

2. Upgrade to google-ads-api@20.0.0:

   npm install google-ads-api@20.0.0
   

   Run the same code:

   console.log(result[0].changed_fields)
   // → undefined
   

3. Confirm via direct REST call that the payload still contains changedFields:

   curl -H "Authorization: Bearer <token>" \
        -H "login-customer-id: <loginCustomerId>" \
        -H "developer-token: <token>" \
        -d '{ "query":"SELECT change_event.changed_fields FROM change_event WHERE change_event.change_date_time DURING LAST_7_DAYS" }' \
        https://googleads.googleapis.com/v20/customers/<cid>/googleAds:search
   

   The JSON response will include "changedFields": { "paths": […] }.

Expected Behavior

The changed_fields property on each returned row should be a parsed object (e.g. { paths: string[] }), matching the behavior in v19.0.2.

Actual Behavior

In v20.0.0 and later, the changed_fields property is always undefined, despite the REST payload containing it.