Create export dialog and async import export utils

src/components/views/dialogs/ExportDialog.tsx

@@ -0,0 +1,56 @@
+import React from 'react';
+import { Room } from 'matrix-js-sdk/src';
+import { _t } from '../../../languageHandler';
+import { IDialogProps } from './IDialogProps';
+import BaseDialog from "./BaseDialog"
+import DialogButtons from "../elements/DialogButtons";
+
+interface IProps extends IDialogProps{
+    room: Room;
+}
+
+export default class ExportDialog extends React.PureComponent<IProps> {
+    onExportClick = async () => {
+        const {
+            default: exportConversationalHistory,
+            exportFormats,
+            exportTypes,
+        } = await import("../../../utils/exportUtils/exportUtils");
+
+        await exportConversationalHistory(
+            this.props.room,
+            exportFormats.PLAIN_TEXT,
+            exportTypes.START_DATE,
+            {
+                startDate: parseInt(new Date("2021.05.20").getTime().toFixed(0)),
+                attachmentsIncluded: true,
+                maxSize: 7 * 1024 * 1024, // 7 MB
+            },
+        );
+    };
+
+    onCancel = () => {
+        this.props.onFinished(false);
+    };
+
+    render() {
+        return (
+            <BaseDialog
+                title={_t("Export Chat")}
+                contentId='mx_Dialog_content'
+                hasCancel={true}
+                onFinished={this.props.onFinished}
+                fixedWidth={false}
+            >
+                <div className="mx_Dialog_content" id='mx_Dialog_content'>
+                    Export
+                </div>
+                <DialogButtons
+                    primaryButton={_t('Export')}
+                    onPrimaryButtonClick={this.onExportClick}
+                    onCancel={this.onCancel}
+                />
+            </BaseDialog>
+        );
+    }
+}