Module "public/match"

match

• match<TIn, TInExt, TOut>(ifInstanceOf: Ctor<TInExt>, then: MapFnOrValue<TInExt, TOut>): MatchExecutor<TIn, TOut>
• match<TIn, TInExt, TOut>(ifIsType: (val: TIn) => val is TInExt, then: MapFnOrValue<TInExt, TOut>): MatchExecutor<TIn, TOut>
• match<TIn, TOut>(ifTrue: (val: TIn) => boolean, then: MapFnOrValue<TIn, TOut>): MatchExecutor<TIn, TOut>
• match<TIn, TOut>(ifEquals: () => TIn, then: MapFnOrValue<TIn, TOut>): MatchExecutor<TIn, TOut>
• match<TIn, TOut, TStructure>(ifMatches: TStructure, then: MapFnOrValue<TIn, TOut>): MatchExecutor<TIn, TOut>

• description

  Match if val is an instance of a Constructor

  since

  1.0.0

  example

  import { match, strike, otherwise } from 'matchbook';
  
  // Get the level of Personal Protective Equipment for each career
  class Human { }
  class Nurse extends Human { }
  class ConstructionWorker extends Human { }
  class BombSquadTechnician extends Human { }
  
  const actual = strike(
      new Nurse(),
      match(Nurse, PpeLevel.Low),
      match(ConstructionWorker, PpeLevel.Medium),
      match(BombSquadTechnician, PpeLevel.High),
      otherwise(Ppe.None),
  );
  
  assertEq(actual, PpeLevel.Low);

  Type parameters

  • TIn

  • TInExt: TIn

  • TOut

  Parameters

  • ifInstanceOf: Ctor<TInExt>

  • then: MapFnOrValue<TInExt, TOut>

  Returns MatchExecutor<TIn, TOut>

• description

  Match if val satisfies a Type Guard

  since

  1.0.0

  example

  import { match, strike, otherwise } from 'matchbook';
  
  const actual = strike<unknown, string>(
      4,
      match(
          n => typeof n === 'number',
          // NOTE: Even though we're matching on type unknown,
          //   since our type guard is satisfied,
          //   this delegate knows n is a number.
          n => `sqrt: ${Math.sqrt(n)}`
      ),
      otherwise('no clue')
  );
  
  assertEq(actual, 'sqrt: 2');

  Type parameters

  • TIn

  • TInExt: TIn

  • TOut

  Parameters

  • ifIsType: (val: TIn) => val is TInExt

    • • (val: TIn): val is TInExt

      • Parameters

        • val: TIn

        Returns val is TInExt

  • then: MapFnOrValue<TInExt, TOut>

  Returns MatchExecutor<TIn, TOut>

• description

  Match if val satisfies a Predicate

  since

  1.0.0

  example

  import { match, strike, otherwise } from 'matchbook';
  
  const actual = strike(
      '     ',
      match(s => s.trim() === '', `that's empty! nice try!`),
      otherwise('not empty!'),
  );
  
  assertEq(actual, `that's empty! outrageous!`);

  Type parameters

  • TIn

  • TOut

  Parameters

  • ifTrue: (val: TIn) => boolean

    • • (val: TIn): boolean

      • Parameters

        • val: TIn

        Returns boolean

  • then: MapFnOrValue<TIn, TOut>

  Returns MatchExecutor<TIn, TOut>

• description

  Match if val equals a lazy value

  since

  1.0.0

  example

  import { match, strike, otherwise } from 'matchbook';
  
  enum Emoji {
      Smiley = '😊',
      Sad = '😢',
      Eggplant = '🍆'
  }
  
  function getMostPopularEmoji() {
      return Emoji.Eggplant;
  }
  
  const actual = strike(
      '🍆',
      match(getMostPopularEmoji, 'very popular!'),
      otherwise('not popular...')
  );
  
  assertEq(actual, 'very popular!');

  Type parameters

  • TIn

  • TOut

  Parameters

  • ifEquals: () => TIn

    • • (): TIn

      • Returns TIn

  • then: MapFnOrValue<TIn, TOut>

  Returns MatchExecutor<TIn, TOut>

• description

  Match if val matches part of another

  since

  1.0.0

  example

  import { match, pattern, otherwise } from 'matchbook';
  
  const getGoodBirthdayGift = pattern(
      match({ hobby: Hobby.Golf }, 'golf cart'),
      match({ hobby: Hobby.Woodworking }, 'table saw'),
      match({ hobby: Hobby.Blacksmithing }, 'tongs'),
      otherwise('money')
  );
  
  const steve = {
      name: 'Steve',
      hobby: Hobby.Woodworking,
  };
  
  assertEq(getGoodBirthdayGift(steve), 'table saw');

  Type parameters

  • TIn

  • TOut

  • TStructure: Partial<TIn>

  Parameters

  • ifMatches: TStructure

  • then: MapFnOrValue<TIn, TOut>

  Returns MatchExecutor<TIn, TOut>