Generated by XState Viz: https://xstate.js.org/viz

machine.js

  // Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions
  // - XState (all XState exports)
  
  function isKey(key) {
    return function(_, evt) {
      return evt.which === key;
    };
  }
  
  function *buildStatesSequences([initial, ...sequences]) {
    let [, firstState] = initial;
    let current = firstState;
    function keyState(key, target) {
      return {
        [current]: {
          on: {
            KEYUP: [
              { target, cond: isKey(key) },
              { target: firstState }
            ]
          }
        }
      };
    }
    for (let [key, target] of sequences) {
      yield keyState(key, target);
      current = target;
    }
    yield { [current]: { type: 'final' } };
  }

  const fetchMachine = Machine({
    id: 'konami',
    initial: 'idle',
    states: Object.assign(
      ...buildStatesSequences([
        [null, 'idle'],
        ['keyUP', 'up1'],
        ['keyUP', 'up2'],
        ['keyDOWN', 'down1'],
        ['keyDOWN', 'down2'],
        ['keyLEFT', 'left1'],
        ['keyRIGHT', 'right1'],
        ['keyLEFT', 'left2'],
        ['keyRIGHT', 'right2'],
        ['keyB', 'b'],
        ['keyA', 'a']
      ])
    )
  });