in packages/geofire-common/src/index.ts [206:217]
export function metersToLongitudeDegrees(distance: number, latitude: number): number {
const radians = degreesToRadians(latitude);
const num = Math.cos(radians) * EARTH_EQ_RADIUS * Math.PI / 180;
const denom = 1 / Math.sqrt(1 - E2 * Math.sin(radians) * Math.sin(radians));
const deltaDeg = num * denom;
if (deltaDeg < EPSILON) {
return distance > 0 ? 360 : 0;
}
else {
return Math.min(360, distance / deltaDeg);
}
}