[](https://www.npmjs.com/package/@polymer/iron-resizable-behavior) [](https://travis-ci.org/PolymerElements/iron-resizable-behavior) [](https://webcomponents.org/element/@polymer/iron-resizable-behavior) ## IronResizableBehavior `IronResizableBehavior` is a behavior that can be used in Polymer elements to coordinate the flow of resize events between "resizers" (elements that control the size or hidden state of their children) and "resizables" (elements that need to be notified when they are resized or un-hidden by their parents in order to take action on their new measurements). Elements that perform measurement should add the `IronResizableBehavior` behavior to their element definition and listen for the `iron-resize` event on themselves. This event will be fired when they become showing after having been hidden, when they are resized explicitly by another resizable, or when the window has been resized. Note, the `iron-resize` event is non-bubbling. See: [Documentation](https://www.webcomponents.org/element/@polymer/iron-resizable-behavior), [Demo](https://www.webcomponents.org/element/@polymer/iron-resizable-behavior/demo/demo/index.html). ## Usage ### Installation ``` npm install --save @polymer/iron-resizable-behavior ``` ### In a Polymer 3 element ```js import {PolymerElement, html} from '@polymer/polymer'; import {mixinBehaviors} from '@polymer/polymer/lib/legacy/class.js'; import {IronResizableBehavior} from '@polymer/iron-resizable-behavior/iron-resizable-behavior.js'; class SampleElement extends mixinBehaviors([IronResizableBehavior], PolymerElement) { static get template() { return html` width: [[width]] height: [[height]] `; } static get properties() { return { width: Number, height: Number, } } connectedCallback() { super.connectedCallback(); this.addEventListener('iron-resize', this.onIronResize.bind(this)); } onIronResize() { this.width = this.offsetWidth; this.height = this.offsetHeight; } } customElements.define('sample-element', SampleElement); ``` ## Contributing If you want to send a PR to this element, here are the instructions for running the tests and demo locally: ### Installation ```sh git clone https://github.com/PolymerElements/iron-resizable-behavior cd iron-resizable-behavior npm install npm install -g polymer-cli ``` ### Running the demo locally ```sh polymer serve --npm open http://127.0.0.1:/demo/ ``` ### Running the tests ```sh polymer test --npm ```