Add a simple TagComposer for the keywords entry

src/components/views/elements/TagComposer.tsx

@@ -0,0 +1,91 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+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, { ChangeEvent, FormEvent } from "react";
+import { replaceableComponent } from "../../../utils/replaceableComponent";
+import Field from "./Field";
+import { _t } from "../../../languageHandler";
+import AccessibleButton from "./AccessibleButton";
+
+interface IProps {
+    tags: string[];
+    onAdd: (tag: string) => void;
+    onRemove: (tag: string) => void;
+    disabled?: boolean;
+    label?: string;
+    placeholder?: string;
+}
+
+interface IState {
+    newTag: string;
+}
+
+/**
+ * A simple, controlled, composer for entering string tags. Contains a simple
+ * input, add button, and per-tag remove button.
+ */
+@replaceableComponent("views.elements.TagComposer")
+export default class TagComposer extends React.PureComponent<IProps, IState> {
+    public constructor(props: IProps) {
+        super(props);
+
+        this.state = {
+            newTag: "",
+        };
+    }
+
+    private onInputChange = (ev: ChangeEvent<HTMLInputElement>) => {
+        this.setState({ newTag: ev.target.value });
+    };
+
+    private onAdd = (ev: FormEvent) => {
+        ev.preventDefault();
+        if (!this.state.newTag) return;
+
+        this.props.onAdd(this.state.newTag);
+        this.setState({ newTag: "" });
+    };
+
+    private onRemove = (tag: string) => {
+        // We probably don't need to proxy this, but for
+        // sanity of `this` we'll do so anyways.
+        this.props.onRemove(tag);
+    };
+
+    public render() {
+        return <div className='mx_TagComposer'>
+            <form className='mx_TagComposer_input' onSubmit={this.onAdd}>
+                <Field
+                    value={this.state.newTag}
+                    onChange={this.onInputChange}
+                    label={this.props.label || _t("Keyword")}
+                    placeholder={this.props.placeholder || _t("New keyword")}
+                    disabled={this.props.disabled}
+                    autoComplete="off"
+                />
+                <AccessibleButton onClick={this.onAdd} kind='primary' disabled={this.props.disabled}>
+                    { _t("Add") }
+                </AccessibleButton>
+            </form>
+            <div className='mx_TagComposer_tags'>
+                { this.props.tags.map((t, i) => (<div className='mx_TagComposer_tag' key={i}>
+                    <span>{ t }</span>
+                    <AccessibleButton onClick={this.onRemove.bind(this, t)} disabled={this.props.disabled} />
+                </div>)) }
+            </div>
+        </div>;
+    }
+}