Approximate Pi from Random Points

You are given an array `pts` of points sampled uniformly at random from the unit square `[0, 1] x [0, 1]`. Each point is represented as an array `[x, y]`, where `0 <= x <= 1` and `0 <= y <= 1`. A point lies inside the quarter circle of radius `1` if: `x^2 + y^2 <= 1` Implement the following function to return an approximation of the value of `pi`: ```javascript function approx(pts) { return 0; } ``` Use the fraction of points that fall inside the quarter circle to estimate `pi`. Constraints: - `pts` is never `null`. - `pts` contains at least one point. - Every point contains exactly two numeric values.