A package to calculate the geothmetic meandian for you.
import {geothmeticMeandian} from "geothmetic-meandian";
console.log(geothmeticMeandian([1, 1, 2, 3, 5])) // 2.089...
// You can also specify the convergence accuracy (default is 0.001):
console.log(geothmeticMeandian([1, 1, 2, 3, 5], 0.000001)) // 2.089058...