mirror of
https://github.com/element-hq/element-web.git
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63 lines
2.1 KiB
JavaScript
63 lines
2.1 KiB
JavaScript
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/*
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Copyright 2018 New Vector Ltd
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import React from "react";
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import AutoHideScrollbar from "./AutoHideScrollbar";
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export default class IndicatorScrollbar extends React.Component {
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constructor(props) {
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super(props);
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this._collectScroller = this._collectScroller.bind(this);
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this.checkOverflow = this.checkOverflow.bind(this);
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}
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_collectScroller(scroller) {
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if (scroller && !this._scroller) {
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this._scroller = scroller;
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this._scroller.addEventListener("scroll", this.checkOverflow);
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this.checkOverflow();
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}
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}
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checkOverflow() {
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const hasTopOverflow = this._scroller.scrollTop > 0;
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const hasBottomOverflow = this._scroller.scrollHeight >
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(this._scroller.scrollTop + this._scroller.clientHeight);
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if (hasTopOverflow) {
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this._scroller.classList.add("mx_IndicatorScrollbar_topOverflow");
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} else {
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this._scroller.classList.remove("mx_IndicatorScrollbar_topOverflow");
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}
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if (hasBottomOverflow) {
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this._scroller.classList.add("mx_IndicatorScrollbar_bottomOverflow");
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} else {
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this._scroller.classList.remove("mx_IndicatorScrollbar_bottomOverflow");
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}
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}
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componentWillUnmount() {
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if (this._scroller) {
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this._scroller.removeEventListener("scroll", this.checkOverflow);
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}
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}
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render() {
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return (<AutoHideScrollbar wrappedRef={this._collectScroller} {... this.props}>
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{ this.props.children }
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</AutoHideScrollbar>);
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}
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}
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