function main(projectId, zone, instanceName, cpuSeries, coreCount, memory) {
  // [START compute_custom_machine_type_extra_mem_no_helper]
  /**
   * TODO(developer): Uncomment and replace these variables before running the sample.
   */
  // const projectId = 'YOUR_PROJECT_ID';
  // const zone = 'europe-central2-b';
  // const instanceName = 'YOUR_INSTANCE_NAME';
  // const cpuSeries = 'N1';
  // const coreCount = 2
  // const memory = 256

  // The coreCount and memory values are not validated anywhere and can be rejected by the API.

  const compute = require('@google-cloud/compute');

  async function createInstanceWithExtraMemWithoutHelper() {
    const instancesClient = new compute.InstancesClient();

    const machineType = `zones/${zone}/machineTypes/${cpuSeries}-${coreCount}-${memory}-ext`;

    const [response] = await instancesClient.insert({
      instanceResource: {
        name: instanceName,
        disks: [
          {
            initializeParams: {
              diskSizeGb: '64',
              sourceImage:
                'projects/debian-cloud/global/images/family/debian-11/',
            },
            autoDelete: true,
            boot: true,
          },
        ],
        machineType,
        networkInterfaces: [
          {
            name: 'global/networks/default',
          },
        ],
      },
      project: projectId,
      zone,
    });
    let operation = response.latestResponse;
    const operationsClient = new compute.ZoneOperationsClient();

    // Wait for the create operation to complete.
    while (operation.status !== 'DONE') {
      [operation] = await operationsClient.wait({
        operation: operation.name,
        project: projectId,
        zone: operation.zone.split('/').pop(),
      });
    }

    console.log('Instance created.');
  }

  createInstanceWithExtraMemWithoutHelper();
  // [END compute_custom_machine_type_extra_mem_no_helper]
}
Creates new VM instances with extra memory without using a CustomMachineType class.

@param {string} projectId - ID or number of the project you want to use.
@param {string} zone - Name of the zone you want to use, for example: us-west3-b
@param {string} instanceName - Name of the new machine.
@param {string} cpuSeries - Type of CPU you want to use.
@param {int} coreCount - Number of CPU cores you want to use.
@param {int} memory - The amount of memory for the VM instance, in megabytes.