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HTML

              
                
              
            
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CSS

              
                
              
            
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JS

              
                console.clear();

// ======== BASIC ========
console.group('basics');

// ### Example function
const createChallenge = (name, opponent, game) => {
  console.log(`${name} is challenging ${opponent} to play a game of ${game}!`);
};

// ### Curried version of example function
const curriedChallengeBasic = name => {
  return opponent => {
      return game => {
        // console.log(`${name}, is challenging ${opponent} to play a game of ${game}!`);
        createChallenge(name, opponent, game);
      };
  };
};

createChallenge('Chantal', 'Mark', 'chess');
curriedChallengeBasic('John')('Sam')('set');

console.groupEnd();
// ======== GENERATED CURRY ========
console.group('generated curry');

const curry = (functionToCurry) => {
  const waitForArguments = (...attrs) => {
    return attrs.length === functionToCurry.length ?
      functionToCurry(...attrs) :
      (...nextAttrs) => waitForArguments(...attrs, ...nextAttrs);
  };

  return waitForArguments;
};

const curriedChallengeGenerated = curry(createChallenge);

curriedChallengeGenerated('Rob')('Patricia')('rummikub');
curriedChallengeGenerated('Mary', 'Linda', 'skip-bo');

console.groupEnd();
// ======== CURRY WITH ARITY ========
console.group('Curry with arity');

const curryWithArity = (functionToCurry, arity = functionToCurry.length) => {
  const waitForArguments = (...attrs) => {
    return attrs.length >= arity ?
      functionToCurry(...attrs) :
      (...nextAttrs) => waitForArguments(...attrs, ...nextAttrs);
  };

  return waitForArguments;
};

const sumTo100 = (...args) => {
  const sum = args.reduce((total, number) => total + number);
  console.log(`${args.join(' + ')}`, sum === 100);
};

const sumTo100In2Parts = curryWithArity(sumTo100, 2);
sumTo100In2Parts(20, 80); // true
sumTo100In2Parts(40)(60); // true

const sumTo100In5Parts = curryWithArity(sumTo100, 5);
sumTo100In5Parts(10, 20, 30, 10, 30); // true
const firstThree = sumTo100In5Parts(10, 20, 30); // function waiting for arguments
firstThree(10, 30); // true

console.groupEnd();
// ======== CURRY WITH PLACEHOLDERS ========
console.group('Curry with placeholders');
const _ = Symbol();

const curryWithPlaceholder = (functionToCurry, numberOfArguments = functionToCurry.length) => {
  const waitForArguments = (...attrs) => {
    const waitForMoreArguments = (...nextAttrs) => {
      const filledAttrs = attrs.map(attr => {
        // if any of attrs is placeholder _, nextAttrs should first fill that
        return attr === _ && nextAttrs.length ?
          nextAttrs.shift() :
          attr;
      });
      return waitForArguments(...filledAttrs, ...nextAttrs);
    };

    // wait for all arguments to be present and not skipped
    return attrs.filter(arg => arg !== _).length >= numberOfArguments ?
      functionToCurry(...attrs) :
      waitForMoreArguments;
  };

  return waitForArguments;
};

const curriedChallengeWithPlaceholder = curryWithPlaceholder(createChallenge);

const playScrabble = curriedChallengeWithPlaceholder(_, _, 'scrabble');
const playTicTacToe = curriedChallengeWithPlaceholder(_, _, 'tic tac toe');

playScrabble('Amy', 'James');
playScrabble('Ben', 'Nicole');
playTicTacToe('Anna', 'Joyce');
playTicTacToe('Thomas', 'Daniel');

console.groupEnd();
              
            
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