turf/packages/turf-boolean-clockwise/test.js

const glob = require("glob");
const path = require("path");
const test = require("tape");
const load = require("load-json-file");
const { lineString } = require("@turf/helpers");
const isClockwise = require("./dist/js/index.js").default;

test("isClockwise#fixtures", (t) => {
  // True Fixtures
  glob
    .sync(path.join(__dirname, "test", "true", "*.geojson"))
    .forEach((filepath) => {
      const name = path.parse(filepath).name;
      const geojson = load.sync(filepath);
      const feature = geojson.features[0];
      t.true(isClockwise(feature), "[true] " + name);
    });
  // False Fixtures
  glob
    .sync(path.join(__dirname, "test", "false", "*.geojson"))
    .forEach((filepath) => {
      const name = path.parse(filepath).name;
      const geojson = load.sync(filepath);
      const feature = geojson.features[0];
      t.false(isClockwise(feature), "[false] " + name);
    });
  t.end();
});

test("isClockwise", (t) => {
  const cwArray = [
    [0, 0],
    [1, 1],
    [1, 0],
    [0, 0],
  ];
  const ccwArray = [
    [0, 0],
    [1, 0],
    [1, 1],
    [0, 0],
  ];

  t.equal(isClockwise(cwArray), true, "[true] clockwise array input");
  t.equal(
    isClockwise(ccwArray),
    false,
    "[false] counter-clockwise array input"
  );

  t.end();
});

test("isClockwise -- Geometry types", (t) => {
  const line = lineString([
    [0, 0],
    [1, 1],
    [1, 0],
    [0, 0],
  ]);

  t.equal(isClockwise(line), true, "Feature");
  t.equal(isClockwise(line.geometry), true, "Geometry Object");

  t.end();
});

// test('isClockwise -- throws', t => {
//     const pt = point([-10, -33]);
//     t.throws(() => isClockwise(pt), 'feature geometry not supported');

//     t.end();
// });