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iron-scroll-threshold - Vaadin Add-on Directory

Polymer element for triggering an event when nearing the beginning or end of a scrollable element iron-scroll-threshold - Vaadin Add-on Directory
[![Published on NPM](https://img.shields.io/npm/v/@polymer/iron-scroll-threshold.svg)](https://www.npmjs.com/package/@polymer/iron-scroll-threshold) [![Build status](https://travis-ci.org/PolymerElements/iron-scroll-threshold.svg?branch=master)](https://travis-ci.org/PolymerElements/iron-scroll-threshold) [![Published on webcomponents.org](https://img.shields.io/badge/webcomponents.org-published-blue.svg)](https://webcomponents.org/element/@polymer/iron-scroll-threshold) ## <iron-scroll-threshold> `iron-scroll-threshold` is a utility element that listens for `scroll` events from a scrollable region and fires events to indicate when the scroller has reached a pre-defined limit, specified in pixels from the upper and lower bounds of the scrollable region. This element may wrap a scrollable region and will listen for `scroll` events bubbling through it from its children. In this case, care should be taken that only one scrollable region with the same orientation as this element is contained within. Alternatively, the `scrollTarget` property can be set/bound to a non-child scrollable region, from which it will listen for events. Once a threshold has been reached, a `lower-threshold` or `upper-threshold` event will be fired, at which point the user may perform actions such as lazily-loading more data to be displayed. After any work is done, the user must then clear the threshold by calling the `clearTriggers` method on this element, after which it will begin listening again for the scroll position to reach the threshold again assuming the content in the scrollable region has grown. If the user no longer wishes to receive events (e.g. all data has been exhausted), the threshold property in question (e.g. `lowerThreshold`) may be set to a falsy value to disable events and clear the associated triggered property. See: [Documentation](https://www.webcomponents.org/element/@polymer/iron-scroll-threshold), [Demo](https://www.webcomponents.org/element/@polymer/iron-scroll-threshold/demo/demo/index.html). ## Usage ### Installation ``` npm install --save @polymer/iron-scroll-threshold ``` ### In an html file ```html
content
 ``` ### In a Polymer 3 element ```js import {PolymerElement, html} from '@polymer/polymer'; import '@polymer/iron-scroll-threshold/iron-scroll-threshold.js'; class SampleElement extends PolymerElement { static get template() { return html`
content
 `; } _loadMoreData: function() { console.log('lower-threshold triggered'); // load async stuff. e.g. XHR setTimeout(() => { this.$.ironScrollTheshold.clearTriggers(); }); } } 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-scroll-threshold cd iron-scroll-threshold 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 ```
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iron-scroll-threshold version 1.0.0
### Dependencies * polymer#Polymer/polymer#^1.1.0 * iron-scroll-target-behavior#PolymerElements/iron-scroll-target-behavior#^1.0.0

iron-scroll-threshold version 1.0.1
### Dependencies * polymer#Polymer/polymer#^1.1.0 * iron-scroll-target-behavior#PolymerElements/iron-scroll-target-behavior#^1.0.0

iron-scroll-threshold version 0.0.1
### Dependencies * @polymer/polymer#^1.2.5-npm-test.2 * @polymer/iron-scroll-target-behavior#^0.0.1

iron-scroll-threshold version 0.0.3
### Dependencies * @polymer/polymer#^1.2.5-npm-test.2 * @polymer/iron-scroll-target-behavior#^0.0.3

iron-scroll-threshold version 1.0.2
### Dependencies * polymer#Polymer/polymer#^1.1.0 * iron-scroll-target-behavior#PolymerElements/iron-scroll-target-behavior#^1.0.0

iron-scroll-threshold version 1.0.3
### Dependencies * polymer#Polymer/polymer#^1.1.0 * iron-scroll-target-behavior#PolymerElements/iron-scroll-target-behavior#^1.0.0

iron-scroll-threshold version 2.0.0
### Dependencies * polymer#Polymer/polymer#1.9 - 2 * iron-scroll-target-behavior#PolymerElements/iron-scroll-target-behavior#1 - 2

iron-scroll-threshold version 3.0.0-pre.1
### Dependencies * @polymer/polymer#^3.0.0-pre.1 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.1

iron-scroll-threshold version 3.0.0-pre.2
### Dependencies * @polymer/polymer#^3.0.0-pre.1 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.1

iron-scroll-threshold version 3.0.0-pre.3
### Dependencies * @polymer/polymer#^3.0.0-pre.3 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.3

iron-scroll-threshold version 3.0.0-pre.4
### Dependencies * @polymer/polymer#^3.0.0-pre.4 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.4

iron-scroll-threshold version 3.0.0-pre.6
### Dependencies * @polymer/polymer#^3.0.0-pre.6 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.6

iron-scroll-threshold version 3.0.0-pre.7
### Dependencies * @polymer/polymer#^3.0.0-pre.7 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.7

iron-scroll-threshold version 3.0.0-pre.8
### Dependencies * @polymer/polymer#^3.0.0-pre.7 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.7

iron-scroll-threshold version 3.0.0-pre.10
### Dependencies * @polymer/polymer#^3.0.0-pre.10 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.10

iron-scroll-threshold version 3.0.0-pre.11
### Dependencies * @polymer/polymer#^3.0.0-pre.10 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.10

iron-scroll-threshold version 3.0.0-pre.12
### Dependencies * @polymer/polymer#3.0.0-pre.12 * @polymer/iron-scroll-target-behavior#3.0.0-pre.12

iron-scroll-threshold version 3.0.0-pre.13
### Dependencies * @polymer/polymer#^3.0.0-pre.13 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.13

iron-scroll-threshold version 3.0.0-pre.14
### Dependencies * @polymer/polymer#^3.0.0-pre.13 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.14

iron-scroll-threshold version 3.0.0-pre.15
### Dependencies * @polymer/polymer#^3.0.0-pre.13 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.15

iron-scroll-threshold version 3.0.0-pre.16
### Dependencies * @polymer/polymer#^3.0.0-pre.13 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.16

iron-scroll-threshold version 3.0.0-pre.17
### Dependencies * @polymer/polymer#^3.0.0-pre.13 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.17

iron-scroll-threshold version 3.0.0-pre.18
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.18

iron-scroll-threshold version 3.0.0-pre.19
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.19

iron-scroll-threshold version 3.0.0-pre.20
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.20

iron-scroll-threshold version 3.0.0-pre.21
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.21

iron-scroll-threshold version 3.0.0-pre.22
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.20

iron-scroll-threshold version 3.0.0-pre.23
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.22

iron-scroll-threshold version 3.0.0-pre.24
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.22

iron-scroll-threshold version 3.0.0-pre.25
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.24

iron-scroll-threshold version 3.0.0-pre.26
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.25

iron-scroll-threshold version 3.0.0
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.26

iron-scroll-threshold version 3.0.1
### Dependencies * @polymer/polymer#^3.0.0 * @polymer/iron-scroll-target-behavior#^3.0.0-pre.26