grid-utils.test.js

/* eslint-env mocha */

const assert = require("assert");
const _ = require("lodash");
const gridUtils = require("./grid-utils");

describe("grid utils", function() {
  describe("cells", function() {
    it("returns all cells of the grid, with coordinates", function() {
      const cells = gridUtils.cells([[1, 2, 3], [4, 5, 6]]);
      assert.deepEqual(cells, [
        { x: 0, y: 0, value: 1 },
        { x: 1, y: 0, value: 2 },
        { x: 2, y: 0, value: 3 },
        { x: 0, y: 1, value: 4 },
        { x: 1, y: 1, value: 5 },
        { x: 2, y: 1, value: 6 }
      ]);
    });
  });

  describe("each", function() {
    it("iterates", function() {
      const iterated = [];
      gridUtils.forEach([[1, 2], [3, 4]], (value, x, y) =>
        iterated.push({ x, y, value })
      );
      assert.deepEqual(iterated, [
        { x: 0, y: 0, value: 1 },
        { x: 1, y: 0, value: 2 },
        { x: 0, y: 1, value: 3 },
        { x: 1, y: 1, value: 4 }
      ]);
    });
  });

  describe("map", function() {
    it("produces a new grid", function() {
      const grid = [];
      assert.notStrictEqual(gridUtils.map(grid, _.identity), grid);
    });

    it("transforms every value in the grid using f", function() {
      const grid = [[1, 2], [3, 4]];
      const newGrid = gridUtils.map(grid, i => i + 1);
      assert.deepEqual(newGrid, [[2, 3], [4, 5]]);
    });
  });

  describe("transpose", function() {
    it("transposes a square", function() {
      assert.deepEqual(gridUtils.transpose([[1, 2], [3, 4]]), [[1, 3], [2, 4]]);
    });

    it("transposes a rectangle", function() {
      assert.deepEqual(gridUtils.transpose([[1, 2, 3], [4, 5, 6]]), [
        [1, 4],
        [2, 5],
        [3, 6]
      ]);
    });
  });
});