feat: add geometry trapezoid

Author: saahil-mahato

Geometry/Test/Trapezoid.test.js

@@ -0,0 +1,93 @@
+import Trapezoid from '../Trapezoid'
+
+describe('Trapezoid', () => {
+  describe('Constructor', () => {
+    test('creates a trapezoid with valid dimensions', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid).toBeInstanceOf(Trapezoid)
+      expect(trapezoid.base1).toBe(5)
+      expect(trapezoid.base2).toBe(10)
+      expect(trapezoid.height).toBe(7)
+      expect(trapezoid.sides).toEqual([null, null])
+    })
+
+    test('creates a trapezoid with all sides known', () => {
+      const trapezoid = new Trapezoid(5, 10, 7, 3, 4)
+      expect(trapezoid.sides).toEqual([3, 4])
+    })
+
+    test('throws an error if any dimension is invalid', () => {
+      expect(() => new Trapezoid(-5, 10, 7)).toThrow(
+        'base1 must be a positive number.'
+      )
+      expect(() => new Trapezoid(5, -10, -7)).toThrow(
+        'base2 must be a positive number.'
+      )
+      expect(() => new Trapezoid(5, NaN, 7)).toThrow(
+        'base2 must be a positive number.'
+      )
+      expect(() => new Trapezoid(5, 10, -7)).toThrow(
+        'height must be a positive number.'
+      )
+    })
+  })
+
+  describe('Area Calculation', () => {
+    test('calculates area correctly', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid.area()).toBe(52.5) // Area = ((5 + 10) / 2) * 7
+    })
+  })
+
+  describe('Perimeter Calculation', () => {
+    test('calculates perimeter correctly when all sides are known', () => {
+      const trapezoid = new Trapezoid(5, 10, 7, 3, 4)
+      expect(trapezoid.perimeter()).toBe(22) // Perimeter = base1 + base2 + sideA + sideB
+    })
+
+    test('throws an error if not all sides are known', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(() => trapezoid.perimeter()).toThrow(
+        'Cannot calculate perimeter: not all sides are known.'
+      )
+    })
+  })
+
+  describe('Getters', () => {
+    test('base1 getter returns correct value', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid.base1).toBe(5)
+    })
+
+    test('base2 getter returns correct value', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid.base2).toBe(10)
+    })
+
+    test('height getter returns correct value', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid.height).toBe(7)
+    })
+
+    test('sides getter returns correct values', () => {
+      const trapezoid = new Trapezoid(5, 10, 7, 3, 4)
+      expect(trapezoid.sides).toEqual([3, 4])
+    })
+  })
+
+  describe('String Representation', () => {
+    test('returns correct string representation when sides are unknown', () => {
+      const trapezoid = new Trapezoid(5, 10, 7)
+      expect(trapezoid.toString()).toBe(
+        'Trapezoid: base1 = 5, base2 = 10, height = 7, sideA = unknown, sideB = unknown, area = 52.5, perimeter = unknown'
+      )
+    })
+
+    test('returns correct string representation when all sides are known', () => {
+      const trapezoid = new Trapezoid(5, 10, 7, 3, 4)
+      expect(trapezoid.toString()).toBe(
+        'Trapezoid: base1 = 5, base2 = 10, height = 7, sideA = 3, sideB = 4, area = 52.5, perimeter = 22'
+      )
+    })
+  })
+})

Geometry/Trapezoid.js

@@ -0,0 +1,141 @@
+/**
+ * This class represents a Trapezoid and provides methods to calculate its area and perimeter.
+ * @see {@link https://en.wikipedia.org/wiki/Trapezoid|Trapezoid}
+ * @class
+ */
+export default class Trapezoid {
+  /** @private */
+  #base1
+
+  /** @private */
+  #base2
+
+  /** @private */
+  #height
+
+  /** @private */
+  #sideA
+
+  /** @private */
+  #sideB
+
+  /**
+   * Creates a trapezoid instance.
+   * @constructor
+   * @param {number} base1 - The length of the first base.
+   * @param {number} base2 - The length of the second base.
+   * @param {number} height - The height of the trapezoid.
+   * @param {number} [sideA] - The length of side A (optional).
+   * @param {number} [sideB] - The length of side B (optional).
+   * @throws {Error} Will throw an error if any dimension is invalid.
+   */
+  constructor(base1, base2, height, sideA = null, sideB = null) {
+    this.#validateDimension(base1, 'base1')
+    this.#validateDimension(base2, 'base2')
+    this.#validateDimension(height, 'height')
+
+    this.#base1 = base1
+    this.#base2 = base2
+    this.#height = height
+    this.#sideA = sideA
+    this.#sideB = sideB
+  }
+
+  /**
+   * 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 trapezoid.
+   * @public
+   * @returns {number} The area of the trapezoid.
+   */
+  area() {
+    return ((this.#base1 + this.#base2) / 2) * this.#height
+  }
+
+  /**
+   * Calculates the perimeter of the trapezoid.
+   * @public
+   * @returns {number} The perimeter of the trapezoid.
+   * @throws {Error} Will throw an error if not all sides are known.
+   */
+  perimeter() {
+    if (this.#sideA === null || this.#sideB === null) {
+      throw new Error('Cannot calculate perimeter: not all sides are known.')
+    }
+    return this.#base1 + this.#base2 + this.#sideA + this.#sideB
+  }
+
+  /**
+   * Returns a string representation of the trapezoid.
+   * @public
+   * @returns {string} A string describing the trapezoid's dimensions and area/perimeter.
+   */
+  toString() {
+    const areaValue = this.area()
+    let perimeterValue
+
+    // Check if all sides are known for perimeter calculation
+    if (this.#sideA === null || this.#sideB === null) {
+      perimeterValue = 'unknown'
+    } else {
+      perimeterValue = this.perimeter()
+    }
+
+    return (
+      `Trapezoid: base1 = ${this.#base1}, base2 = ${this.#base2}, height = ${
+        this.#height
+      }, ` +
+      `sideA = ${this.#sideA ?? 'unknown'}, sideB = ${
+        this.#sideB ?? 'unknown'
+      }, ` +
+      `area = ${areaValue}, perimeter = ${perimeterValue}`
+    )
+  }
+
+  /**
+   * Gets the first base of the trapezoid.
+   * @public
+   * @returns {number} The first base of the trapezoid.
+   */
+  get base1() {
+    return this.#base1
+  }
+
+  /**
+   * Gets the second base of the trapezoid.
+   * @public
+   * @returns {number} The second base of the trapezoid.
+   */
+  get base2() {
+    return this.#base2
+  }
+
+  /**
+   * Gets the height of the trapezoid.
+   * @public
+   * @returns {number} The height of the trapezoid.
+   */
+  get height() {
+    return this.#height
+  }
+
+  /**
+   * Gets the lengths of sides A and B of the trapezoid.
+   * @public
+   * @returns {Array<number|null>} An array containing lengths of side A and side B or null for unknown sides.
+   */
+  get sides() {
+    return [this.#sideA, this.#sideB]
+  }
+}