Replace array element in fp-ts

Question

How would I go about replacing the string cat with dog in the array below?

My example below is a mix of standard js and fp-ts, was curious if there was something in the Array module that would solve this.

const animals = ['monkey','cat','lion']

const result = pipe(
    animals,
    A.findIndex((animal)=> animal === 'cat'),
    O.matchW(
      () => animals,
      (index) => //Looking for fp-ts solution here
    )
  )

//Expected Result: ['monkey','dog','lion']

Do you want to replace only the first occurrence or all of them? — Denis Frezzato, Aug 24 '21 at 12:49

Jonathan Southern · Accepted Answer · 2021-08-25T18:02:43.057

0

I would use A.updateAt. Notice I also wrap O.none condition result so they both conditions return an Option<string[]>

O.matchW(
  () => O.some(animals),
  (index) => A.updateAt(index, 'dog')(animals)
)

edited Aug 25 '21 at 18:02

answered Aug 19 '21 at 15:53

Jonathan Southern

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2

`Option` this is wrong, `Option` has one type variable. – Denis Frezzato Aug 24 '21 at 12:49
@DenisFrezzato You're completely right, edited the post correctly. – Jonathan Southern Aug 25 '21 at 18:03

Replace array element in fp-ts

1 Answers1