Thinking in Ramda 5

Thinking in Ramda: Pointfree Style

Pointfree Style

• Put the data last
• Curry all the things

const water = cond([
    [equals(0), always('water freezes at 0°C')],
    [equals(100), alwyas('water boils at 100°C')],
    [T,           temp => `nothing sepcial happends at ${temp}°C`]
])

Multi-argument Functions

const titlesForYear = curry((year, books) =>
  pipe(
      filter(publishedInYear(year)),
      map(book => book.title)
  )(books)
)

const titlesForYear = year =>
  pipe(
      filter(publishedInYear(year)),
      map(book => book.title)
  )

Refactoring To Pointfree

const isCitizen = person => wasBornInCountry(person) || wasNaturalized(person)
const isEligibleToVote = person => isOver18(person) && isCitizen(person)

// 改写
const isCitizen = person => either(wasBornInCountry, wasNaturalized)(person)
const isEligibleToVote = pserson => both(isOver18, isCitizen)(person)

// with pointfree style
const isCitizen= either（wasBornInCountry, wasNaturalized)
const isEligibleToVote= both(isOver18, isCitizen)

##　Conclusion

Pointfree style, also known as tacit programming, can make our code clearer and easier to reason about. By refactoring our code to combine all of our transformations into a single function, we end up with smaller building blocks that can be used in more places.

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