StoreAppLevelSecret.js

const { SecretManagerServiceClient } = require('@google-cloud/secret-manager');

const secretManagerclient = new SecretManagerServiceClient();
const parent = 'projects/<YourProjectId>';
const tokenId = <YourTokenId>

async function storeAppLevelSecret(appLevelSecretToStore) {
    const [secret] = await secretManagerclient.createSecret({
        parent: parent,
        secretId: tokenId,
        secret: {
            replication: {
                automatic: {},
            },
        },
    });

    console.log(`Created ${secret}`);
  
    const payload = Buffer.from(appLevelSecretToStore, 'utf8');

    const [version] = await client.addSecretVersion({
        parent: secret.name,
        payload: {
            data: payload,
        },
    });
    console.log(version.name);
}