var postgismvt = require('tilestrata-postgismvt');

server.layer('mylayer').route('tile.mvt')
  .use(postgismvt({
    lyr: {
      table: 'schema.table',
      geometry: 'geom',
      type: 'circle',
      srid: 4326,
      minZoom: 3,
      maxZoom: 19,
      buffer: 10
      fields: 'name gid',
      resolution: 256,
    },
    pgConfig: {
      host: 'localhost',
      user: 'postgres',
      password: 'mypassword',
      database: 'postgres',
      port: '5432'
    }}))
  );

server.layer('mylayer').route('tile.mvt')
  .use(postgismvt({
    lyr: {
      ...
      mode: 'cluster'
    },
    pgConfig: {
      ...
    }}))
  );

server.layer('mylayer').route('tile.mvt')
  .use(postgismvt({
    lyr: {
      ...
      mode: 'cluster_fields'
    },
    pgConfig: {
      ...
    }}))
  );

server.layer('mylayer').route('tile.mvt')
  .use(postgismvt({
    lyr: {
      resolution: function(server, req) {
        if (req.z > 12) return 512;
        return 256;
      },
      mode: function(server, req) {
        if (req.z > 15) return null;
        if (req.z > 13) return 'cluster_fields';
        return 'cluster';
      }
    },
    pgConfig: {
      ...
    }}))
  );