Function matchEither

Takes two functions and an Either value, if the value is a Left the inner value is applied to the first function, if the value is a Right the inner value is applied to the second function.

Example

import { match, left, right } from 'fp-ts/Either'
import { pipe } from 'fp-ts/function'

function onLeft(errors: Array<string>): string {
  return `Errors: ${errors.join(', ')}`
}

function onRight(value: number): string {
  return `Ok: ${value}`
}

assert.strictEqual(
  pipe(
    right(1),
    match(onLeft, onRight)
  ),
  'Ok: 1'
)
assert.strictEqual(
  pipe(
    left(['error 1', 'error 2']),
    match(onLeft, onRight)
  ),
  'Errors: error 1, error 2'
)
Copy

Since

2.10.0