const fetchMethodOption = `method: '${verb.toUpperCase()}'`;
const ignoreContentTypes = ['multipart/form-data'];

// Build global fetch options and header merging safely without fragile string slicing
let globalFetchOptions = '';
let fetchHeadersOption = '';

if (isObject(override.requestOptions)) {
  const stringifiedOverrideRequestOptions = stringify(override.requestOptions)?.trim();
  // Spread the whole override.requestOptions first. An explicit headers: { ... } entry added below
  // will override any headers property from the spread (so we don't need to remove headers here).
  const overrideOptionsSpread = stringifiedOverrideRequestOptions ? `...${stringifiedOverrideRequestOptions},` : '';

  const headerFragments: string[] = [];
  if (isObject(override.requestOptions.headers)) {
    const stringifiedOverrideHeaders = stringify(override.requestOptions.headers)?.trim();
    if (stringifiedOverrideHeaders) {
      // include as a spread of the literal object, e.g. ...{ a: 1 }
      headerFragments.push(`...${stringifiedOverrideHeaders}`);
    }
  }
  if (headers) headerFragments.push('...headers');
  if (isRequestOptions) headerFragments.push('...options?.headers');

  fetchHeadersOption = headerFragments.length > 0 ? `headers: { ${headerFragments.join(', ')} }` : '';
  // Put the override spread into globalFetchOptions (it may include many top-level options).
  // Note: trailing comma included to make concatenation in the template simpler.
  globalFetchOptions = overrideOptionsSpread;
} else {
  const headerFragments: string[] = [];
  if (headers) headerFragments.push('...headers');
  if (isRequestOptions) headerFragments.push('...options?.headers');
  fetchHeadersOption = headerFragments.length > 0 ? `headers: { ${headerFragments.join(', ')} }` : '';
  globalFetchOptions = '';
}