@enact/core/snapshot/snapshot.js

Enact is an open source JavaScript framework containing everything you need to create a fast, scalable mobile or web application.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;
exports.isWindowReady = isWindowReady;
exports.onWindowReady = onWindowReady;
exports.windowReady = windowReady;
var _invariant = _interopRequireDefault(require("invariant"));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { "default": e }; }
/**
 * Utilities to facilitate integration with v8 snapshot builds
 *
 * @module core/snapshot
 * @exports isWindowReady
 * @exports onWindowReady
 * @exports windowReady
 * @public
 */

var windowCallbacks = [];

/**
 * Determines if the `window` is available
 *
 * @function
 *
 * @returns {Boolean} `true` when `window` is ready
 * @memberof core/snapshot
 * @public
 */
function isWindowReady() {
  return typeof window !== 'undefined';
}

/**
 * Executes a callback, such as registering event handlers, when a valid `window` is available.
 *
 * During normal operation, the callback will be executed immediately. During a pre-rendering pass,
 * the callback is not be executed at all. When using snapshot, the callback is added to a queue
 * and is executed in order once the window is available.
 *
 * *Important Notes*
 * * The callback should not alter the initial HTML state. If it does, it will invalidate the
 * pre-render state and interfere with React rehydration.
 * * The callback should be limited to module-scoped actions and not component instance actions. If
 * the action is tied to a component, it should be invoked from within the component's lifecycle
 * methods.
 *
 * @function
 * @param   {Function}    callback    Function to run when the window is ready
 *
 * @returns {undefined}
 * @memberof core/snapshot
 * @public
 */
function onWindowReady(callback) {
  if (isWindowReady()) {
    callback();
  } else {
    windowCallbacks.push(callback);
  }
}

/**
 * Executes all queued window callbacks.
 *
 * Requires that the window be, in fact, available and will throw an `Error` if not.
 *
 * @function
 *
 * @returns {undefined}
 * @memberof core/snapshot
 * @public
 */
function windowReady() {
  !isWindowReady() ? process.env.NODE_ENV !== "production" ? (0, _invariant["default"])(false, 'windowReady cannot be run until the window is available') : (0, _invariant["default"])(false) : void 0;
  windowCallbacks.forEach(function (f) {
    return f();
  });
}
var _default = exports["default"] = onWindowReady;