next-csrf/example/node_modules/ally.js/observe/interaction-type.js

CSRF mitigation library for Next.js

'use strict';

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

var _decorateService = require('../util/decorate-service');

var _decorateService2 = _interopRequireDefault(_decorateService);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

// counters to track primary input
var _activePointers = 0;
/*
  Observe keyboard-, pointer-, mouse- and touch-events so that a query for
  the current interaction type can be made at any time. For pointer interaction
  this observer is limited to pointer button down/up - move is not observed!

  USAGE:
    var listener = engage();
    listener.get() === {pointer: Boolean, key: Boolean}
*/

var _activeKeys = 0;

var pointerStartEvents = ['touchstart', 'pointerdown', 'MSPointerDown', 'mousedown'];
var pointerEndEvents = ['touchend', 'touchcancel', 'pointerup', 'MSPointerUp', 'pointercancel', 'MSPointerCancel', 'mouseup'];

function handleWindowBlurEvent() {
  // reset internal counters when window loses focus
  _activePointers = 0;
  _activeKeys = 0;
}

function handlePointerStartEvent(event) {
  if (event.isPrimary === false) {
    // ignore non-primary pointer events
    // https://w3c.github.io/pointerevents/#widl-PointerEvent-isPrimary
    return;
  }

  // mousedown without following mouseup
  // (likely not possible in Chrome)
  _activePointers++;
}

function handlePointerEndEvent(event) {
  if (event.isPrimary === false) {
    // ignore non-primary pointer events
    // https://w3c.github.io/pointerevents/#widl-PointerEvent-isPrimary
    return;
  } else if (event.touches) {
    _activePointers = event.touches.length;
    return;
  }

  // delay reset to when the current handlers are executed
  (window.setImmediate || window.setTimeout)(function () {
    // mouseup without prior mousedown
    // (drag something out of the window)
    _activePointers = Math.max(_activePointers - 1, 0);
  });
}

function handleKeyStartEvent(event) {
  // ignore modifier keys
  switch (event.keyCode || event.which) {
    case 16: // space
    case 17: // control
    case 18: // alt
    case 91: // command left
    case 93:
      // command right
      return;
  }

  // keydown without a following keyup
  // (may happen on CMD+TAB)
  _activeKeys++;
}

function handleKeyEndEvent(event) {
  // ignore modifier keys
  switch (event.keyCode || event.which) {
    case 16: // space
    case 17: // control
    case 18: // alt
    case 91: // command left
    case 93:
      // command right
      return;
  }

  // delay reset to when the current handlers are executed
  (window.setImmediate || window.setTimeout)(function () {
    // keyup without prior keydown
    // (may happen on CMD+R)
    _activeKeys = Math.max(_activeKeys - 1, 0);
  });
}

function getInteractionType() {
  return {
    pointer: Boolean(_activePointers),
    key: Boolean(_activeKeys)
  };
}

function disengage() {
  _activePointers = _activeKeys = 0;
  window.removeEventListener('blur', handleWindowBlurEvent, false);
  document.documentElement.removeEventListener('keydown', handleKeyStartEvent, true);
  document.documentElement.removeEventListener('keyup', handleKeyEndEvent, true);
  pointerStartEvents.forEach(function (event) {
    document.documentElement.removeEventListener(event, handlePointerStartEvent, true);
  });
  pointerEndEvents.forEach(function (event) {
    document.documentElement.removeEventListener(event, handlePointerEndEvent, true);
  });
}

function engage() {
  // window blur must be in bubble phase so it won't capture regular blurs
  window.addEventListener('blur', handleWindowBlurEvent, false);
  // handlers to identify the method of focus change
  document.documentElement.addEventListener('keydown', handleKeyStartEvent, true);
  document.documentElement.addEventListener('keyup', handleKeyEndEvent, true);
  pointerStartEvents.forEach(function (event) {
    document.documentElement.addEventListener(event, handlePointerStartEvent, true);
  });
  pointerEndEvents.forEach(function (event) {
    document.documentElement.addEventListener(event, handlePointerEndEvent, true);
  });

  return {
    get: getInteractionType
  };
}

exports.default = (0, _decorateService2.default)({ engage: engage, disengage: disengage });
module.exports = exports['default'];
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