Module "xform/match-first"

matchFirst

• matchFirst<T>(pred: Predicate<T>): Transducer<T, T>
• matchFirst<T>(pred: Predicate<T>, src: Iterable<T>): T | undefined

• Transducer composition / syntax sugar for:

  example

  comp(filter(pred), take(1))

  Yields none or only the first value which passed the predicate check and then causes early termination. If src input is given, returns first match found (or undefined). Also see {@link (matchLast:1)}.

  example

  matchFirst((x) => x >= 5, [3, 1, 4, 2, 6, 5])
  // 6
  
  transduce(
    comp(
      matchFirst((x) => x >= 5),
      map((x) => x * 10)
    ),
    last(),
    [3, 1, 4, 2, 6, 5]
  )
  // 60

  Type parameters

  • T

  Parameters

  • pred: Predicate<T>

    predicate function

  Returns Transducer<T, T>

• Type parameters

  • T

  Parameters

  • pred: Predicate<T>

  • src: Iterable<T>

  Returns T | undefined