import {Map} from './shims/es6-collections.js';
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import ResizeObserverController from './ResizeObserverController.js';
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import ResizeObserverSPI from './ResizeObserverSPI.js';
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// Registry of internal observers. If WeakMap is not available use current shim
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// for the Map collection as it has all required methods and because WeakMap
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// can't be fully polyfilled anyway.
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const observers = typeof WeakMap !== 'undefined' ? new WeakMap() : new Map();
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/**
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* ResizeObserver API. Encapsulates the ResizeObserver SPI implementation
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* exposing only those methods and properties that are defined in the spec.
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*/
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class ResizeObserver {
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/**
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* Creates a new instance of ResizeObserver.
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*
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* @param {ResizeObserverCallback} callback - Callback that is invoked when
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* dimensions of the observed elements change.
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*/
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constructor(callback) {
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if (!(this instanceof ResizeObserver)) {
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throw new TypeError('Cannot call a class as a function.');
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}
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if (!arguments.length) {
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throw new TypeError('1 argument required, but only 0 present.');
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}
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const controller = ResizeObserverController.getInstance();
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const observer = new ResizeObserverSPI(callback, controller, this);
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observers.set(this, observer);
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}
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}
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// Expose public methods of ResizeObserver.
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[
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'observe',
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'unobserve',
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'disconnect'
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].forEach(method => {
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ResizeObserver.prototype[method] = function () {
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return observers.get(this)[method](...arguments);
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};
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});
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export default ResizeObserver;
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