import { Curve } from "https://deno.land/x/threejs_4_deno@v121/src/extras/core/Curve.d.ts";
Returns a unit vector tangent at t. If the subclassed curve do not implement its tangent derivation, 2 points a small delta apart will be used to find its gradient which seems to give a reasonable approximation getTangent(t: number, optionalTarget?: T): T;