feat: add geometry ellipse

Geometry/Ellipse.js

@@ -0,0 +1,95 @@
+/**
+ * This class represents an Ellipse and provides methods to calculate its area and circumference.
+ * @see {@link https://en.wikipedia.org/wiki/Ellipse}
+ * @class
+ */
+export default class Ellipse {
+  /** @private */
+  #radiusX
+
+  /** @private */
+  #radiusY
+
+  /**
+   * Creates an ellipse instance.
+   * @constructor
+   * @param {number} radiusX - The radius along the x-axis.
+   * @param {number} radiusY - The radius along the y-axis.
+   * @throws {Error} Will throw an error if any dimension is invalid.
+   */
+  constructor(radiusX, radiusY) {
+    this.#validateDimension(radiusX, 'radiusX')
+    this.#validateDimension(radiusY, 'radiusY')
+
+    this.#radiusX = radiusX
+    this.#radiusY = radiusY
+  }
+
+  /**
+   * Validates that a dimension is a positive number.
+   * @private
+   * @param {number} value - The value to validate.
+   * @param {string} name - The name of the dimension (for error reporting).
+   * @throws {Error} Will throw an error if the value is not a positive number.
+   */
+  #validateDimension(value, name) {
+    if (typeof value !== 'number' || isNaN(value) || value <= 0) {
+      throw new Error(`${name} must be a positive number.`)
+    }
+  }
+
+  /**
+   * Calculates the area of the ellipse.
+   * @public
+   * @returns {number} The area of the ellipse.
+   */
+  area() {
+    return Math.PI * this.#radiusX * this.#radiusY
+  }
+
+  /**
+   * Calculates the circumference of the ellipse using Ramanujan's approximation.
+   * @public
+   * @returns {number} The circumference of the ellipse.
+   */
+  circumference() {
+    return (
+      Math.PI *
+      (3 * (this.#radiusX + this.#radiusY) -
+        Math.sqrt(
+          (3 * this.#radiusX + this.#radiusY) *
+            (this.#radiusX + 3 * this.#radiusY)
+        ))
+    )
+  }
+
+  /**
+   * Returns a string representation of the ellipse.
+   * @public
+   * @returns {string} A string describing the ellipse's dimensions and area/circumference.
+   */
+  toString() {
+    return (
+      `Ellipse: radiusX = ${this.#radiusX}, radiusY = ${this.#radiusY}, ` +
+      `area = ${this.area()}, circumference = ${this.circumference()}`
+    )
+  }
+
+  /**
+   * Gets the radius along the x-axis.
+   * @public
+   * @returns {number} The radius along the x-axis.
+   */
+  get radiusX() {
+    return this.#radiusX
+  }
+
+  /**
+   * Gets the radius along the y-axis.
+   * @public
+   * @returns {number} The radius along the y-axis.
+   */
+  get radiusY() {
+    return this.#radiusY
+  }
+}

Geometry/Test/Ellipse.test.js

@@ -0,0 +1,68 @@
+import Ellipse from '../Ellipse'
+
+describe('Ellipse', () => {
+  describe('Constructor', () => {
+    test('creates an ellipse with valid dimensions', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse).toBeInstanceOf(Ellipse)
+      expect(ellipse.radiusX).toBe(5)
+      expect(ellipse.radiusY).toBe(10)
+    })
+
+    test('throws an error if any dimension is invalid', () => {
+      expect(() => new Ellipse(-5, 10)).toThrow(
+        'radiusX must be a positive number.'
+      )
+      expect(() => new Ellipse(5, -10)).toThrow(
+        'radiusY must be a positive number.'
+      )
+      expect(() => new Ellipse(NaN, 10)).toThrow(
+        'radiusX must be a positive number.'
+      )
+      expect(() => new Ellipse(5, undefined)).toThrow(
+        'radiusY must be a positive number.'
+      )
+    })
+  })
+
+  describe('Area Calculation', () => {
+    test('calculates area correctly', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse.area()).toBeCloseTo(Math.PI * 5 * 10) // Area = π * rX * rY
+    })
+  })
+
+  describe('Circumference Calculation', () => {
+    test('calculates circumference correctly', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse.circumference()).toBeCloseTo(
+        Math.PI * (3 * (5 + 10) - Math.sqrt((3 * 5 + 10) * (5 + 3 * 10)))
+      ) // Circumference using Ramanujan's approximation
+    })
+  })
+
+  describe('Getters', () => {
+    test('radiusX getter returns correct value', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse.radiusX).toBe(5)
+    })
+
+    test('radiusY getter returns correct value', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse.radiusY).toBe(10)
+    })
+  })
+
+  describe('String Representation', () => {
+    test('returns correct string representation', () => {
+      const ellipse = new Ellipse(5, 10)
+      expect(ellipse.toString()).toBe(
+        `Ellipse: radiusX = 5, radiusY = 10, area = ${
+          Math.PI * 5 * 10
+        }, circumference = ${
+          Math.PI * (3 * (5 + 10) - Math.sqrt((3 * 5 + 10) * (5 + 3 * 10)))
+        }`
+      )
+    })
+  })
+})