[Ch09] before vs. after

ch9/01-1.js

@@ -5,18 +5,24 @@ const scenario = {
   delay: 40,
 }
 
-const distanceTravelled = (scenario, time) => {
-  let result
-  let acc = scenario.primaryForce / scenario.mass // (a = F / m)
-  let primaryTime = Math.min(time, scenario.delay)
-  result = 0.5 * acc * primaryTime ** 2
-  let secondaryTime = time - scenario.delay
-  if (secondaryTime > 0) {
-    let primaryVelocity = acc * scenario.delay
-    acc = (scenario.primaryForce + scenario.secondaryForce) / scenario.mass
-    result += primaryVelocity * secondaryTime + 0.5 * acc * secondaryTime ** 2
-  }
-  return result
+// 가속도 = 힘 / 무게
+const acceleration = (force, mass) => force / mass
+
+// 가속운동시 거리 = 1/2 * a * t^2
+const acceleratedDistance = (acc, time) => (acc * time ** 2) / 2
+
+// 등속운동시 거리 = 속도 * 시간
+const sameVelocityDistance = (velocity, time) => velocity * time
+
+const distanceTravelled = ({ primaryForce, secondaryForce, mass, delay }, time) => {
+  const primaryAcceleration = acceleration(primaryForce, mass)
+  const secondaryAcceleration = acceleration(primaryForce + secondaryForce, mass)
+  const secondaryTime = Math.max(time - delay, 0)
+  return (
+    acceleratedDistance(primaryAcceleration, Math.min(time, delay)) +
+    acceleratedDistance(secondaryAcceleration, secondaryTime) +
+    sameVelocityDistance(primaryAcceleration * delay, secondaryTime)
+  )
 }
 
 console.log(distanceTravelled(scenario, 100))

ch9/01-2.js

@@ -1,7 +1,8 @@
 const discount = (inputValue, quantity) => {
-  if (inputValue > 50) inputValue = inputValue - 2
-  if (quantity > 100) inputValue = inputValue - 1
-  return inputValue
+  let result = inputValue
+  if (inputValue > 50) result = result - 2
+  if (quantity > 100) result = result - 1
+  return result
 }
 console.log(discount(40, 90))
 console.log(discount(70, 90))

ch9/02.js

@@ -1,15 +1,15 @@
 class Organization {
-  #name
+  #title
   #country
   constructor(data) {
-    this.#name = data.name
+    this.#title = data.title
     this.#country = data.country
   }
-  get name() {
-    return this.#name
+  get title() {
+    return this.#title
   }
-  set name(aString) {
-    this.#name = aString
+  set title(aString) {
+    this.#title = aString
   }
   get country() {
     return this.#country
@@ -18,4 +18,5 @@ class Organization {
     this.#country = aCountry
   }
 }
-const organization = new Organization({ name: '애크미 구스베리', country: 'GB' })
+const organization = new Organization({ title: '애크미 구스베리', country: 'GB' })
+console.log(organization.title)

ch9/03-1.js

@@ -1,12 +1,14 @@
 class ProductionPlan {
-  #production = 0
   #adjustments = []
   get production() {
-    return this.#production
+    return this.calculatedProduction
   }
+  get calculatedProduction() {
+    return this.#adjustments.reduce((sum, a) => sum + a.amount, 0)
+  }
+
   applyAdjustment(anAdjustment) {
     this.#adjustments.push(anAdjustment)
-    this.#production += anAdjustment.amount
   }
 }
 

ch9/03-2.js

@@ -1,15 +1,19 @@
 class ProductionPlan {
-  #production = 0
+  #initialProduction
   #adjustments = []
   constructor(production) {
-    this.#production = production
+    this.#initialProduction = production
+    this.#adjustments = []
   }
   get production() {
-    return this.#production
+    return this.#initialProduction + this.calculatedProductionAccumulator
   }
+  get calculatedProductionAccumulator() {
+    return this.#adjustments.reduce((sum, a) => sum + a.amount, 0)
+  }
+
   applyAdjustment(anAdjustment) {
     this.#adjustments.push(anAdjustment)
-    this.#production += anAdjustment.amount
   }
 }
 

ch9/04.js

@@ -1,6 +1,12 @@
+/* import { assert } from 'chai'
+import { it } from 'mocha' */
 class TelephoneNumber {
   #areaCode
   #number
+  constructor(areaCode, number) {
+    this.#areaCode = areaCode
+    this.#number = number
+  }
   get areaCode() {
     return this.#areaCode
   }
@@ -13,28 +19,50 @@ class TelephoneNumber {
   set number(arg) {
     this.#number = arg
   }
+  equals(other) {
+    if (!(other instanceof TelephoneNumber)) return false
+    return this.#areaCode === other.#areaCode && this.#number === other.#number
+  }
 }
 
 class Person {
   #telephoneNumber
   constructor() {
-    this.#telephoneNumber = new TelephoneNumber()
+    this.#telephoneNumber = new TelephoneNumber('', '')
+  }
+  get telephone() {
+    return this.#telephoneNumber
   }
   get officeAreaCode() {
     return this.#telephoneNumber.areaCode
   }
   set officeAreaCode(arg) {
-    this.#telephoneNumber.areaCode = arg
+    this.#telephoneNumber = new TelephoneNumber(arg, this.officeNumber)
   }
   get officeNumber() {
     return this.#telephoneNumber.number
   }
   set officeNumber(arg) {
-    this.#telephoneNumber.number = arg
+    this.#telephoneNumber = new TelephoneNumber(this.officeAreaCode, arg)
   }
 }
 
-const p = new Person()
-p.officeAreaCode = '312'
-p.officeNumber = '555-0142'
-console.log(p.officeAreaCode, p.officeNumber)
+const p1 = new Person()
+p1.officeAreaCode = '312'
+console.log(p1.officeAreaCode, p1.officeNumber)
+
+p1.officeNumber = '555-0142'
+console.log(p1.officeAreaCode, p1.officeNumber)
+
+/* 
+const p2 = new Person()
+p2.officeAreaCode = '456'
+p2.officeNumber = '777-0342'
+
+console.log(p2.officeAreaCode, p2.officeNumber)
+console.log(p1.officeAreaCode, p1.officeNumber)
+console.log(p1.telephone.areaCode, p2.telephone.areaCode)
+ */
+/* it('telephone equals', () => {
+  assert(new TelephoneNumber('312', '555-0142').equals(new TelephoneNumber('312', '555-0142')))
+}) */

ch9/05.js

@@ -8,17 +8,26 @@ class Customer {
   }
 }
 
+const findCustomer = id => _repositoryData.customers.get(id)
 class Order {
   #number
   #customer
   constructor(data) {
     this.#number = data.number
-    this.#customer = new Customer(data.customer)
+    this.#customer = registerCustomer(data.customer)
   }
   get customer() {
-    return this.#customer
+    return findCustomer(this.#customer)
   }
 }
 
+const _repositoryData = { customers: new Map() }
+const registerCustomer = id => {
+  if (!_repositoryData.customers.has(id)) {
+    _repositoryData.customers.set(id, new Customer(id))
+  }
+  return id
+}
+
 const o = new Order({ number: 1, customer: 'a' })
 console.log(o.customer.id)