Variable tryCatchConst

Example

import * as E from 'fp-ts/Either'

const unsafeHead = <A>(as: ReadonlyArray<A>): A => {
  if (as.length > 0) {
    return as[0]
  } else {
    throw new Error('empty array')
  }
}

const head = <A>(as: ReadonlyArray<A>): E.Either<Error, A> =>
  E.tryCatch(() => unsafeHead(as), e => (e instanceof Error ? e : new Error('unknown error')))

assert.deepStrictEqual(head([]), E.left(new Error('empty array')))
assert.deepStrictEqual(head([1, 2, 3]), E.right(1))
Copy