mvcds

Feature: Configure ages for country
  Given A user from BR
  When getting configuration for drive
  Then the age should be 18
  
  Given A user from SA
  When getting configuration for alcohol
  Then the age does not influence if it is allowed
  
  Given A user from US

mvcds

const defaultConfiguration = {
    alcohol: 21,
    softDrugs: Infinity,
    hardDrugs: Infinity,
    drive: 21,
    adult: 21
}

type Configuration = typeof defaultConfiguration

mvcds

//hard-coded data giving by business (probably) to "play safe"
const defaultConfiguration = {
    alcohol: 21,
    softDrugs: Infinity,
    hardDrugs: Infinity,
    drive: 21,
    adult: 21
}

// ts-magic, creates an interface-like type definition

mvcds

function canBuyProduct({ age }: User, { kind }: Product): boolean {
 const result = age >= this.ageRestriction[kind]
 
 // when debugging, we can create and/or tweak data
 // this way we force the code to flow in the directions that interests the task at hand
 // remember to revert your changes =D
 if (true) {
   logger.warn('front-end exposed user to invalid product')
 }
  

mvcds

// this is hard-coded data
// probably it comes from the business rules
const MIN_POINTS = 5

// the argument is a dynamic data
// it might come from another place on the codebase
// or somewhere else, like a database
function calculateFidelity({ type, experiments }: User, products: [Product]) {
    const points = products.reduce(
        (total,{ fidelityPoints }) => total + fidelityPoints,

mvcds

// canBuyProduct is a simple rule
function canBuyProduct({ age }: User, { kind }: Product): boolean {
 const result = age >= this.ageRestriction[kind]
 
 if (!result) {
   logger.warn('front-end exposed user to invalid product')
 }
  
 return result
}

mvcds

/*old interface
function makeFoo(a: number, b: FooDTO): Foo[] {}
*/

//new interface BAD
function oldMakeFooDontUseIt(a: number, b: FooDTO): Foo[] {}
function newFooMaking(a: FooDTO, b: boolean, c: number): Foo[] {}

//new interface GOOD
function makeFoo(a: number, b: FooDTO, c: boolean = false): Foo[] {}

mvcds

//the data modifier transforms the class into a record
//the constructor and destructor are not relevant for the example but make it easier 
public data class Person 
{ 
    string FirstName; 
    string LastName; 
    public Person(string firstName, string lastName) 
      => (FirstName, LastName) = (firstName, lastName);
    public void Deconstruct(out string firstName, out string lastName) 
      => (firstName, lastName) = (FirstName, LastName);

mvcds

(operator first-operand second-operand nth-operand)
; like (+ 1 2 3 5 8 13)

mvcds

{
  "name": "my-use-cases",
  "version": "0.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "my-domain": "0.0.0"
  }
}