1 files changed, 69 insertions, 0 deletions
diff --git a/webapp/components/post_view/new_message_indicator.jsx b/webapp/components/post_view/new_message_indicator.jsx
new file mode 100644
index 000000000..d5fb6c1d3
--- /dev/null
+++ b/webapp/components/post_view/new_message_indicator.jsx
@@ -0,0 +1,69 @@
+// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import React from 'react';
+import PropTypes from 'prop-types';
+import {FormattedMessage} from 'react-intl';
+
+export default class NewMessageIndicator extends React.PureComponent {
+    static propTypes = {
+        onClick: PropTypes.func.isRequired,
+        newMessages: PropTypes.number
+    }
+
+    constructor(props) {
+        super(props);
+        this.state = {
+            visible: false,
+            rendered: false
+        };
+    }
+
+    componentWillReceiveProps(nextProps) {
+        if (nextProps.newMessages > 0) {
+            this.setState({rendered: true}, () => {
+                this.setState({visible: true});
+            });
+        } else {
+            this.setState({visible: false});
+        }
+    }
+
+    render() {
+        let className = 'new-messages__button';
+        if (this.state.visible > 0) {
+            className += ' visible';
+        }
+        if (!this.state.rendered) {
+            className += ' disabled';
+        }
+        return (
+            <div
+                className={className}
+                onTransitionEnd={this.setRendered.bind(this)}
+                ref='indicator'
+            >
+                <div onClick={this.props.onClick}>
+                    <i
+                        className='fa fa-angle-down'
+                    />
+                    <FormattedMessage
+                        id='posts_view.newMsgBelow'
+                        defaultMessage='New {count, plural, one {message} other {messages}} below'
+                        values={{count: this.props.newMessages}}
+                    />
+                </div>
+            </div>
+        );
+    }
+
+    // Sync 'rendered' state with visibility param, only after transitions
+    // have ended
+    setRendered() {
+        this.setState({rendered: this.state.visible});
+    }
+}
+
+NewMessageIndicator.defaultProps = {
+    newMessages: 0
+};