TypeScript tasks

index.ts

// Task 1:

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// TODO: define function argument type

function addOne(numberOrNumbers) {
  if (typeof numberOrNumbers === 'number') {
    return numberOrNumbers + 1
  } else {
    return numberOrNumbers.map(number => number + 1)
  }
}

addOne(100)
addOne([3, 4, 5])

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// Task 2:

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// TODO: define missing LoggerFunction and User types

function inspectUser(loggerFunction: LoggerFunction, user: User) {
   let userDescription = user.fullname ? user.fullname : user.nickname

   if (user.admin) {
     userDescription = `[admin] ${userDescription}`
   }

   loggerFunction(userDescription)
}

inspectUser(console.log, { nickname: 'css-queen-1993' })
inspectUser(console.log, { nickname: 'munchy-box-lover', fullname: "James M." })
inspectUser(console.log, { nickname: 'mihai_t', admin: true })

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// Task 3 - ADVANCED!

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type DarkPaletteColorKeyword = 'black' | 'gray' | 'pink'
type LightPaletteColorKeyword = 'white' | 'gray' | 'blue'

// TODO: define a generic Theme type
// that's an object whose keys are of the given variable type
// and that variable type must extend the string type (`extends string`)

const colorKeywordToHexTheme1: Theme<DarkPaletteColorKeyword> = {
    'black': '#001100',
    'gray': '#555555',
    'pink': '#ffc0cb'
}

const colorKeywordToHexTheme2: Theme<LightPaletteColorKeyword> = {
    'white': '#ffffff',
    'gray': '#ccccc',
    'blue': '#244ba5'
}

// TODO: add type annotations to make this a generic function
// that takes two arguments:
// - first, the colorKeyword argument of the given variable type
// - second, a theme argument of the generic Theme type whose keys are of the given variable type

function colorKeywordToHex(colorKeyword, theme) {
    return theme[colorKeyword]
}

colorKeywordToHex('pink', colorKeywordToHexTheme1)
colorKeywordToHex('white', colorKeywordToHexTheme2)
// comment this out to see an error
// colorKeywordToHex('pink', colorKeywordToHexTheme2)

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