TypeScript implementation of circumcircle finder

circumcircle.ts

import { Vector2 } from 'three';

export function findCircumCircle(vertices: Vector2[]) {
    if (vertices.length === 1) {
        return [vertices[0], 0];
    }
    if (vertices.length === 2) {
        return [
            vertices[0].clone().add(vertices[1]).multiplyScalar(0.5),
            vertices[0].distanceTo(vertices[1]) * 0.5,
        ];
    }
    if (vertices.length !== 3) {
        console.warn(
            `Unexpected number of vertices ${vertices.length}, expect 3`,
        );
    }
    // handle degeneracy
    if (isStrictlyEqual(vertices[0], vertices[1])) {
        return findCircumCircle([vertices[0], vertices[2]]);
    }
    if (isStrictlyEqual(vertices[0], vertices[2])) {
        return findCircumCircle([vertices[0], vertices[1]]);
    }
    if (isStrictlyEqual(vertices[1], vertices[2])) {
        return findCircumCircle([vertices[0], vertices[1]]);
    }

    const x0 = vertices[0].x;
    const x1 = vertices[1].x;
    const x2 = vertices[2].x;
    const y0 = vertices[0].y;
    const y1 = vertices[1].y;
    const y2 = vertices[2].y;
    const s0 = x0 ** 2 + y0 ** 2;
    const s1 = x1 ** 2 + y1 ** 2;
    const s2 = x2 ** 2 + y2 ** 2;

    // https://en.wikipedia.org/wiki/Circumcircle#Circumcenter_coordinates
    const d = 2 * (x0 * (y1 - y2) + x1 * (y2 - y0) + x2 * (y0 - y1));
    const xc = (s0 * (y1 - y2) + s1 * (y2 - y0) + s2 * (y0 - y1)) / d;
    const yc = (s0 * (x2 - x1) + s1 * (x0 - x2) + s2 * (x1 - x0)) / d;
    const r = ((xc - x0) ** 2 + (yc - y0) ** 2) ** 0.5;

    return [new Vector2(xc, yc), r];
}

export function isStrictlyEqual(v1: Vector2, v2: Vector2) {
    return v1.x === v2.x && v1.y === v2.y;
}