djembe/dist/bundle.esm.js

A rhythm maker which emits any data with the given rhythm periodically

function _defineProperty$1(obj, key, value) {
  if (key in obj) {
    Object.defineProperty(obj, key, {
      value: value,
      enumerable: true,
      configurable: true,
      writable: true
    });
  } else {
    obj[key] = value;
  }

  return obj;
}

function ownKeys$1(object, enumerableOnly) {
  var keys = Object.keys(object);

  if (Object.getOwnPropertySymbols) {
    var symbols = Object.getOwnPropertySymbols(object);
    if (enumerableOnly) symbols = symbols.filter(function (sym) {
      return Object.getOwnPropertyDescriptor(object, sym).enumerable;
    });
    keys.push.apply(keys, symbols);
  }

  return keys;
}

function _objectSpread2$1(target) {
  for (var i = 1; i < arguments.length; i++) {
    var source = arguments[i] != null ? arguments[i] : {};

    if (i % 2) {
      ownKeys$1(Object(source), true).forEach(function (key) {
        _defineProperty$1(target, key, source[key]);
      });
    } else if (Object.getOwnPropertyDescriptors) {
      Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
    } else {
      ownKeys$1(Object(source)).forEach(function (key) {
        Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key));
      });
    }
  }

  return target;
}

function _defineProperty(obj, key, value) {
  if (key in obj) {
    Object.defineProperty(obj, key, {
      value: value,
      enumerable: true,
      configurable: true,
      writable: true
    });
  } else {
    obj[key] = value;
  }

  return obj;
}

function ownKeys(object, enumerableOnly) {
  var keys = Object.keys(object);

  if (Object.getOwnPropertySymbols) {
    var symbols = Object.getOwnPropertySymbols(object);
    if (enumerableOnly) symbols = symbols.filter(function (sym) {
      return Object.getOwnPropertyDescriptor(object, sym).enumerable;
    });
    keys.push.apply(keys, symbols);
  }

  return keys;
}

function _objectSpread2(target) {
  for (var i = 1; i < arguments.length; i++) {
    var source = arguments[i] != null ? arguments[i] : {};

    if (i % 2) {
      ownKeys(Object(source), true).forEach(function (key) {
        _defineProperty(target, key, source[key]);
      });
    } else if (Object.getOwnPropertyDescriptors) {
      Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
    } else {
      ownKeys(Object(source)).forEach(function (key) {
        Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key));
      });
    }
  }

  return target;
}

function _toConsumableArray(arr) {
  return _arrayWithoutHoles(arr) || _iterableToArray(arr) || _unsupportedIterableToArray(arr) || _nonIterableSpread();
}

function _arrayWithoutHoles(arr) {
  if (Array.isArray(arr)) return _arrayLikeToArray(arr);
}

function _iterableToArray(iter) {
  if (typeof Symbol !== "undefined" && Symbol.iterator in Object(iter)) return Array.from(iter);
}

function _unsupportedIterableToArray(o, minLen) {
  if (!o) return;
  if (typeof o === "string") return _arrayLikeToArray(o, minLen);
  var n = Object.prototype.toString.call(o).slice(8, -1);
  if (n === "Object" && o.constructor) n = o.constructor.name;
  if (n === "Map" || n === "Set") return Array.from(o);
  if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
}

function _arrayLikeToArray(arr, len) {
  if (len == null || len > arr.length) len = arr.length;

  for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i];

  return arr2;
}

function _nonIterableSpread() {
  throw new TypeError("Invalid attempt to spread non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
}

var DEFAULT_OPTIONS$1 = {
  steps: 32,
  steppers: 7,
  initialState: null
};
function epicles() {
  var options = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

  var mergedOptions = _objectSpread2(_objectSpread2({}, DEFAULT_OPTIONS$1), options);

  var steps = mergedOptions.steps,
      steppers = mergedOptions.steppers,
      initialState = mergedOptions.initialState;

  if (steps < 2) {
    throw new Error('step size must be at least 2');
  }

  if (initialState && initialState.length !== steps) {
    throw new Error('initial state length must be equal to step size');
  }

  var state = initialState ? sanetizeState(initialState) : Array(steppers).fill(0);
  var subscribers = [];

  function sanetizeState(state) {
    return state.map(function (stepper) {
      return stepper > 0 ? stepper % steps : (steps - Math.abs(stepper) % steps) % steps;
    });
  }

  function cyclicIncrement(value) {
    return (value + 1) % steps;
  }

  function emitTickEvent(event) {
    subscribers.forEach(function (subscriber) {
      subscriber(event);
    });
  }

  function increment(state, index) {
    var tickEvents = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : [];

    var nextState = _toConsumableArray(state);

    nextState[index] = cyclicIncrement(nextState[index]);
    tickEvents.push({
      step: nextState[index],
      stepper: index
    });

    if (nextState[index] === 0 && index < state.length - 1) {
      return increment(nextState, index + 1, tickEvents);
    }

    return {
      nextState: nextState,
      tickEvents: tickEvents
    };
  }

  function tick() {
    var _increment = increment(state, 0, []),
        nextState = _increment.nextState,
        tickEvents = _increment.tickEvents;

    state = nextState;
    emitTickEvent(tickEvents);
  }

  function subscribe(callback) {
    if (subscribers.find(callback)) return;
    subscribers.push(callback);

    var unsubscribe = function unsubscribe() {
      subscribers = subscribers.filter(function (subscriber) {
        return subscriber !== callback;
      });
    };

    return unsubscribe;
  }

  function getState() {
    return state.map(function (value, index) {
      return {
        stepper: index,
        step: value
      };
    });
  }

  return {
    tick: tick,
    subscribe: subscribe,
    getState: getState
  };
}

var DEFAULT_OPTIONS = {
  steps: 32,
  steppers: 7,
  ticks: []
};
function Djembe() {
  var opts = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
  var subscribers = [];

  var options = _objectSpread2$1(_objectSpread2$1({}, DEFAULT_OPTIONS), opts);

  var steps = options.steps,
      steppers = options.steppers,
      initialState = options.initialState;
  var ticks = options.ticks;
  var epicle = epicles({
    steps: steps,
    steppers: steppers,
    initialState: initialState
  });
  epicle.subscribe(handleTickEvents);

  function handleTickEvents(events) {
    var emittedTicks = ticks.filter(function (tick) {
      var shouldBeEmitted = !!events.find(function (event) {
        return event.step === tick.step && event.stepper === tick.stepper;
      });
      return shouldBeEmitted;
    });
    var state = epicle.getState();
    emit(emittedTicks, state);
  }

  function emit(ticks, state) {
    subscribers.forEach(function (subscriber) {
      subscriber({
        ticks: ticks,
        state: state
      });
    });
  }

  function tick() {
    epicle.tick();
  }

  function subscribe(callback) {
    if (subscribers.find(callback)) return;
    subscribers.push(callback);

    var unsubscribe = function unsubscribe() {
      subscribers = subscribers.filter(function (subscriber) {
        return subscriber !== callback;
      });
    };

    return unsubscribe;
  }

  function setTicks(nextTicks) {
    ticks = nextTicks;
  }

  return {
    subscribe: subscribe,
    tick: tick,
    setTicks: setTicks
  };
}

export { Djembe };