xstate/lib/State.js

Finite State Machines and Statecharts for the Modern Web.

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var _tslib = require('./_virtual/_tslib.js');
var constants = require('./constants.js');
var utils = require('./utils.js');
var stateUtils = require('./stateUtils.js');
var actions = require('./actions.js');
var environment = require('./environment.js');

function stateValuesEqual(a, b) {
  if (a === b) {
    return true;
  }

  if (a === undefined || b === undefined) {
    return false;
  }

  if (utils.isString(a) || utils.isString(b)) {
    return a === b;
  }

  var aKeys = Object.keys(a);
  var bKeys = Object.keys(b);
  return aKeys.length === bKeys.length && aKeys.every(function (key) {
    return stateValuesEqual(a[key], b[key]);
  });
}
function isStateConfig(state) {
  if (typeof state !== 'object' || state === null) {
    return false;
  }

  return 'value' in state && '_event' in state;
}
/**
 * @deprecated Use `isStateConfig(object)` or `state instanceof State` instead.
 */

var isState = isStateConfig;
function bindActionToState(action, state) {
  var exec = action.exec;

  var boundAction = _tslib.__assign(_tslib.__assign({}, action), {
    exec: exec !== undefined ? function () {
      return exec(state.context, state.event, {
        action: action,
        state: state,
        _event: state._event
      });
    } : undefined
  });

  return boundAction;
}

var State =
/*#__PURE__*/

/** @class */
function () {
  /**
   * Creates a new State instance.
   * @param value The state value
   * @param context The extended state
   * @param historyValue The tree representing historical values of the state nodes
   * @param history The previous state
   * @param actions An array of action objects to execute as side-effects
   * @param activities A mapping of activities and whether they are started (`true`) or stopped (`false`).
   * @param meta
   * @param events Internal event queue. Should be empty with run-to-completion semantics.
   * @param configuration
   */
  function State(config) {
    var _this = this;

    var _a;

    this.actions = [];
    this.activities = constants.EMPTY_ACTIVITY_MAP;
    this.meta = {};
    this.events = [];
    this.value = config.value;
    this.context = config.context;
    this._event = config._event;
    this._sessionid = config._sessionid;
    this.event = this._event.data;
    this.historyValue = config.historyValue;
    this.history = config.history;
    this.actions = config.actions || [];
    this.activities = config.activities || constants.EMPTY_ACTIVITY_MAP;
    this.meta = stateUtils.getMeta(config.configuration);
    this.events = config.events || [];
    this.matches = this.matches.bind(this);
    this.toStrings = this.toStrings.bind(this);
    this.configuration = config.configuration;
    this.transitions = config.transitions;
    this.children = config.children;
    this.done = !!config.done;
    this.tags = (_a = Array.isArray(config.tags) ? new Set(config.tags) : config.tags) !== null && _a !== void 0 ? _a : new Set();
    this.machine = config.machine;
    Object.defineProperty(this, 'nextEvents', {
      get: function () {
        return stateUtils.nextEvents(_this.configuration);
      }
    });
  }
  /**
   * Creates a new State instance for the given `stateValue` and `context`.
   * @param stateValue
   * @param context
   */


  State.from = function (stateValue, context) {
    if (stateValue instanceof State) {
      if (stateValue.context !== context) {
        return new State({
          value: stateValue.value,
          context: context,
          _event: stateValue._event,
          _sessionid: null,
          historyValue: stateValue.historyValue,
          history: stateValue.history,
          actions: [],
          activities: stateValue.activities,
          meta: {},
          events: [],
          configuration: [],
          transitions: [],
          children: {}
        });
      }

      return stateValue;
    }

    var _event = actions.initEvent;
    return new State({
      value: stateValue,
      context: context,
      _event: _event,
      _sessionid: null,
      historyValue: undefined,
      history: undefined,
      actions: [],
      activities: undefined,
      meta: undefined,
      events: [],
      configuration: [],
      transitions: [],
      children: {}
    });
  };
  /**
   * Creates a new State instance for the given `config`.
   * @param config The state config
   */


  State.create = function (config) {
    return new State(config);
  };
  /**
   * Creates a new `State` instance for the given `stateValue` and `context` with no actions (side-effects).
   * @param stateValue
   * @param context
   */


  State.inert = function (stateValue, context) {
    if (stateValue instanceof State) {
      if (!stateValue.actions.length) {
        return stateValue;
      }

      var _event = actions.initEvent;
      return new State({
        value: stateValue.value,
        context: context,
        _event: _event,
        _sessionid: null,
        historyValue: stateValue.historyValue,
        history: stateValue.history,
        activities: stateValue.activities,
        configuration: stateValue.configuration,
        transitions: [],
        children: {}
      });
    }

    return State.from(stateValue, context);
  };
  /**
   * Returns an array of all the string leaf state node paths.
   * @param stateValue
   * @param delimiter The character(s) that separate each subpath in the string state node path.
   */


  State.prototype.toStrings = function (stateValue, delimiter) {
    var _this = this;

    if (stateValue === void 0) {
      stateValue = this.value;
    }

    if (delimiter === void 0) {
      delimiter = '.';
    }

    if (utils.isString(stateValue)) {
      return [stateValue];
    }

    var valueKeys = Object.keys(stateValue);
    return valueKeys.concat.apply(valueKeys, _tslib.__spreadArray([], _tslib.__read(valueKeys.map(function (key) {
      return _this.toStrings(stateValue[key], delimiter).map(function (s) {
        return key + delimiter + s;
      });
    })), false));
  };

  State.prototype.toJSON = function () {
    var _a = this;
        _a.configuration;
        _a.transitions;
        var tags = _a.tags;
        _a.machine;
        var jsonValues = _tslib.__rest(_a, ["configuration", "transitions", "tags", "machine"]);

    return _tslib.__assign(_tslib.__assign({}, jsonValues), {
      tags: Array.from(tags)
    });
  };

  State.prototype.matches = function (parentStateValue) {
    return utils.matchesState(parentStateValue, this.value);
  };
  /**
   * Whether the current state configuration has a state node with the specified `tag`.
   * @param tag
   */


  State.prototype.hasTag = function (tag) {
    return this.tags.has(tag);
  };
  /**
   * Determines whether sending the `event` will cause a non-forbidden transition
   * to be selected, even if the transitions have no actions nor
   * change the state value.
   *
   * @param event The event to test
   * @returns Whether the event will cause a transition
   */


  State.prototype.can = function (event) {
    var _a;

    if (environment.IS_PRODUCTION) {
      utils.warn(!!this.machine, "state.can(...) used outside of a machine-created State object; this will always return false.");
    }

    var transitionData = (_a = this.machine) === null || _a === void 0 ? void 0 : _a.getTransitionData(this, event);
    return !!(transitionData === null || transitionData === void 0 ? void 0 : transitionData.transitions.length) && // Check that at least one transition is not forbidden
    transitionData.transitions.some(function (t) {
      return t.target !== undefined || t.actions.length;
    });
  };

  return State;
}();

exports.State = State;
exports.bindActionToState = bindActionToState;
exports.isState = isState;
exports.isStateConfig = isStateConfig;
exports.stateValuesEqual = stateValuesEqual;