Error handling

{
  "error": {
    "code": "invalid_query",
    "message": "invalid query: the query failed 1 validation check"
  },
  "summary": "error: the function `len` does not exist on string\n0: *query*:1\n |\n1 | 'foo'.len()\n  |       ^^^\n  |\n",
  ...
}

const FAUNA_SECRET = '<FAUNA_SECRET>';

async function fetchFaunaData(query, args = {}) {
  try {
    const response = await fetch('https://db.fauna.com/query/1', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${FAUNA_SECRET}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        query: query,
        arguments: args
      })
    });

    const data = await response.json();

    // Check if an error object is present in the response
    if (data.error) {
      handleFaunaError(data.error, response.status);
    } else {
      console.log('Query successful:', data);
      return data;
    }
  } catch (error) {
    console.error('Request failed:', error);
  }
}

// Error handling based on Fauna error codes
/**
  This function contains a description of each
  Fauna error codes and how to handle them.
*/
function handleFaunaError(error, statusCode) {
  switch (error.code) {

    /**
    * An error returned by calling the FQL `abort()` function.
    */
    case 'abort':
      console.error('Transaction aborted:', error.message);
      break;

    /**
    * A runtime error due to failing schema constraints.
    */
    case 'constraint_failure':
      console.error('Constraint failure:', error.message);
      break;

    /**
    * Feature disabled error.
     */
    case 'disabled_feature':
      console.error('Feature disabled:', error.message);
      break;

    /**
    * An error due to a deleted document.
    */
    case 'document_deleted':
      console.error('Document deleted:', error.message);
      break;

    /**
     * An error due to a missing document.
     */
    case 'document_not_found':
      console.error('Document not found:', error.message);
      break;

    /**
    * A type of AuthorizationError that indicates the user does not have
    * privileges to perform requested operations.
    */
    case 'forbidden':
      console.error('Forbidden:', error.message);
      break;

    /**
    * A type of ServiceInternalError indicates Fauna failed unexpectedly.
     */
    case 'internal_error':
      console.error('Internal error:', error.message);
      break;

    /**
    * An error due to an invalid argument or query.
    */
    case 'invalid_argument':
    case 'invalid_computed_field_access':
    case 'invalid_date':
    case 'invalid_effect':
    case 'invalid_id':
    case 'invalid_null_access':
    case 'invalid_regex':
    case 'invalid_schema':
    case 'invalid_time':
    case 'invalid_type':
    case 'invalid_write':
      console.error('Invalid Error:', error.message);
      break;

    /**
    * An error due to invalid method invocation.
    */
    case 'method_not_allowed':
      console.error('Method not allowed:', error.message);
      break;

    /**
    * An error due to a null value.
    */
    case 'null_value':
      console.error('Null value:', error.message);
      break;

    /**
    * Request exceeds the maximum HTTP request payload.
    */
    case 'request_size_exceeded':
      console.error('Request size exceeded:', error.message);
      break;

    /**
    * Type of Authentication Error indicates invalid credentials were
    * used.
    */
    case 'unauthorized':
      console.error('Unauthorized:', error.message);
      break;

    /**
    * Indicates a throughput limit was exceeded
    * and thus the request could not be served.
    */
    case 'limit_exceeded':
      console.error('Limit exceeded:', error.message);
      break;

    /**
    * A failure due to the query timeout being exceeded.
    *
    * This error can have one of two sources:
    *     1. Fauna is behaving expectedly, but the query timeout provided was too
    *        aggressive and lower than the query's expected processing time.
    *     2. Fauna was not available to service the request before the timeout was
    *        reached.
    *
    * In either case, consider increasing the `query_timeout_ms` configuration for
    * your client.
    */
    case 'time_out':
      console.error('Time out:', error.message);
      break;

    /**
    * An error due to a contended transaction.
    */
    case 'contended_transaction':
      console.error('Contended transaction:', error.message);
      break;
  }

  // Log the status code for reference.
  console.error('Status code:', statusCode);
  // You can also log a summary if available.
  if (error.summary) {
    console.error('Error summary:', error.summary);
  }
}