getIntermediatePoint()

in modules/edit-modes/src/lib/draw-90degree-polygon-mode.ts [178:219]

• 35 lines of code
• 6 McCabe index (conditional complexity)

  getIntermediatePoint(coordinates: Position[]) {
    let pt;
    if (coordinates.length > 4) {
      const [p1, p2] = [...coordinates];
      const angle1 = bearing(p1, p2);
      const p3 = coordinates[coordinates.length - 3];
      const p4 = coordinates[coordinates.length - 4];
      const angle2 = bearing(p3, p4);

      const angles = { first: [], second: [] };
      // calculate 3 right angle points for first and last points in lineString
      [1, 2, 3].forEach((factor) => {
        const newAngle1 = angle1 + factor * 90;
        // convert angles to 0 to -180 for anti-clock and 0 to 180 for clock wise
        angles.first.push(newAngle1 > 180 ? newAngle1 - 360 : newAngle1);
        const newAngle2 = angle2 + factor * 90;
        angles.second.push(newAngle2 > 180 ? newAngle2 - 360 : newAngle2);
      });

      const distance = turfDistance(point(p1), point(p3));
      // Draw imaginary right angle lines for both first and last points in lineString
      // If there is intersection point for any 2 lines, will be the 90 degree point.
      [0, 1, 2].forEach((indexFirst) => {
        const line1 = turfLineString([
          p1,
          destination(p1, distance, angles.first[indexFirst]).geometry.coordinates,
        ]);
        [0, 1, 2].forEach((indexSecond) => {
          const line2 = turfLineString([
            p3,
            destination(p3, distance, angles.second[indexSecond]).geometry.coordinates,
          ]);
          const fc = lineIntersect(line1, line2);
          if (fc && fc.features.length) {
            // found the intersect point
            pt = fc.features[0].geometry.coordinates;
          }
        });
      });
    }
    return pt;
  }