How to use the viewport-mercator-project.getMeterZoom function in viewport-mercator-project

} = opts;

    this.id = id || this.constructor.displayName || 'viewport';

    // Check if we have a geospatial anchor
    this.isGeospatial = Number.isFinite(latitude) && Number.isFinite(longitude);

    // Silently allow apps to send in w,h = 0,0
    this.x = x;
    this.y = y;
    this.width = width || 1;
    this.height = height || 1;

    this.zoom = zoom;
    if (!Number.isFinite(this.zoom)) {
      this.zoom = this.isGeospatial ? getMeterZoom({latitude}) : DEFAULT_ZOOM;
    }
    this.scale = Math.pow(2, this.zoom);

    // Calculate distance scales if lng/lat/zoom are provided
    this.distanceScales = this.isGeospatial
      ? getDistanceScales({latitude, longitude, scale: this.scale})
      : distanceScales || DEFAULT_DISTANCE_SCALES;

    this.focalDistance = opts.focalDistance || 1;

    this.distanceScales.metersPerPixel = new Vector3(this.distanceScales.metersPerPixel);
    this.distanceScales.pixelsPerMeter = new Vector3(this.distanceScales.pixelsPerMeter);

    this.position = ZERO_VECTOR;
    this.meterOffset = ZERO_VECTOR;
    if (position) {

test('getMeterZoom', t => {
  const TEST_LATITUDES = [0, 37.5, 75];

  for (const latitude of TEST_LATITUDES) {
    const zoom = getMeterZoom({latitude});

    const {pixelsPerMeter} = getDistanceScales({latitude, longitude: 0, zoom});
    t.deepEqual(toLowPrecision(pixelsPerMeter), [1, -1, 1], 'zoom yields 1 pixel per meter');
  }

  t.end();
});