Add full emoji picker for reactions

Signed-off-by: Tulir Asokan <tulir@maunium.net>

src/components/views/emojipicker/Header.js

@@ -0,0 +1,58 @@
+/*
+Copyright 2019 Tulir Asokan
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import PropTypes from 'prop-types';
+
+import * as icons from "./icons";
+
+class Header extends React.Component {
+    static propTypes = {
+        categories: PropTypes.arrayOf(PropTypes.object).isRequired,
+        onAnchorClick: PropTypes.func.isRequired,
+        defaultCategory: PropTypes.string,
+    };
+
+    constructor(props) {
+        super(props);
+        this.state = {
+            selected: props.defaultCategory || props.categories[0].id,
+        };
+        this.handleClick = this.handleClick.bind(this);
+    }
+
+    handleClick(ev) {
+        const selected = ev.target.getAttribute("data-category-id");
+        this.setState({selected});
+        this.props.onAnchorClick(selected);
+    };
+
+    render() {
+        return (
+            <nav className="mx_EmojiPicker_header">
+                {this.props.categories.map(category => (
+                    <button key={category.id} className={`mx_EmojiPicker_anchor ${
+                        this.state.selected === category.id ? 'mx_EmojiPicker_anchor_selected' : ''}`}
+                        onClick={this.handleClick} data-category-id={category.id} title={category.name}>
+                        {icons.categories[category.id]()}
+                    </button>
+                ))}
+            </nav>
+        )
+    }
+}
+
+export default Header;