export function getCode()

in modules/aggregation-layers/src/contour-layer/marching-squares.js [35:108]
55 lines of code
16 McCabe index (conditional complexity)

export function getCode(opts) {
  // Assumptions
  // Origin is on bottom-left , and X increase to right, Y to top
  // When processing one cell, we process 4 cells, by extending row to top and on column to right
  // to create a 2X2 cell grid
  const {cellWeights, x, y, width, height} = opts;
  let threshold = opts.threshold;
  if (opts.thresholdValue) {
    log.deprecated('thresholdValue', 'threshold')();
    threshold = opts.thresholdValue;
  }

  const isLeftBoundary = x < 0;
  const isRightBoundary = x >= width - 1;
  const isBottomBoundary = y < 0;
  const isTopBoundary = y >= height - 1;
  const isBoundary = isLeftBoundary || isRightBoundary || isBottomBoundary || isTopBoundary;

  const weights = {};
  const codes = {};

  // TOP
  if (isLeftBoundary || isTopBoundary) {
    codes.top = 0;
  } else {
    weights.top = cellWeights[(y + 1) * width + x];
    codes.top = getVertexCode(weights.top, threshold);
  }

  // TOP-RIGHT
  if (isRightBoundary || isTopBoundary) {
    codes.topRight = 0;
  } else {
    weights.topRight = cellWeights[(y + 1) * width + x + 1];
    codes.topRight = getVertexCode(weights.topRight, threshold);
  }

  // RIGHT
  if (isRightBoundary || isBottomBoundary) {
    codes.right = 0;
  } else {
    weights.right = cellWeights[y * width + x + 1];
    codes.right = getVertexCode(weights.right, threshold);
  }

  // CURRENT
  if (isLeftBoundary || isBottomBoundary) {
    codes.current = 0;
  } else {
    weights.current = cellWeights[y * width + x];
    codes.current = getVertexCode(weights.current, threshold);
  }

  const {top, topRight, right, current} = codes;
  let code = -1;
  if (Number.isFinite(threshold)) {
    code = (top << 3) | (topRight << 2) | (right << 1) | current;
  }
  if (Array.isArray(threshold)) {
    code = (top << 6) | (topRight << 4) | (right << 2) | current;
  }

  let meanCode = 0;
  // meanCode is only needed for saddle cases, and they should
  // only occur when we are not processing a cell on boundary
  // because when on a boundary either, bottom-row, top-row, left-column or right-column will have both 0 codes
  if (!isBoundary) {
    meanCode = getVertexCode(
      (weights.top + weights.topRight + weights.right + weights.current) / 4,
      threshold
    );
  }
  return {code, meanCode};
}