add document viewer

- fix markdown viewer

- fix txt viewer

src/renderer/component/fileRender/view.jsx

@@ -3,6 +3,7 @@ import React from 'react';
 import LoadingScreen from 'component/common/loading-screen';
 import PdfViewer from 'component/viewers/pdfViewer';
 import ThreeViewer from 'component/viewers/threeViewer';
+import DocumentViewer from 'component/viewers/documentViewer';
 
 type Props = {
   mediaType: string,
@@ -22,6 +23,7 @@ class FileRender extends React.PureComponent<Props> {
     // Supported mediaTypes
     const mediaTypes = {
       '3D-file': <ThreeViewer {...viewerProps} />,
+      document: <DocumentViewer {...viewerProps} />,
       // Add routes to viewer...
     };
 

src/renderer/component/viewers/documentViewer.jsx

@@ -0,0 +1,80 @@
+// @flow
+
+import React from 'react';
+import fs from 'fs';
+import LoadingScreen from 'component/common/loading-screen';
+import MarkdownPreview from 'component/common/markdown-preview';
+
+type Props = {
+  source: {
+    fileType: string,
+    filePath: string,
+    downloadPath: string,
+  },
+};
+
+class DocumentViewer extends React.PureComponent<Props> {
+  constructor(props) {
+    super(props);
+    this.state = {
+      error: null,
+      content: null,
+      loading: true,
+    };
+  }
+
+  componentDidMount() {
+    const { source } = this.props;
+    const stream = fs.createReadStream(source.downloadPath, 'utf8');
+
+    let data = '';
+
+    stream.on('data', chunk => {
+      data += chunk;
+    });
+
+    stream.on('end', () => {
+      this.setState({ content: data });
+    });
+
+    stream.on('error', error => {
+      this.setState({ error });
+    });
+  }
+
+  renderDocument(data) {
+    const { source } = this.props;
+    const { fileType } = source;
+
+    // Match supported documents
+    const docs = {
+      md: content => <MarkdownPreview content={content} promptLinks />,
+    };
+
+    if (docs[fileType]) {
+      // Use custom parser
+      return docs[fileType](data);
+    }
+    // Render plain text
+    this.setState({ loading: false });
+    return <textarea disabled="true" value={data} />;
+  }
+
+  render() {
+    const { content, error, loading } = this.state;
+    const loadingMessage = __('Rendering document.');
+    const errorMessage = __("Sorry looks like we can't load the document.");
+
+    return (
+      <div className="document-viewer file-render__viewer">
+        {loading && !error && <LoadingScreen status={loadingMessage} spinner />}
+        {error && <LoadingScreen status={errorMessage} spinner={false} />}
+        {content && (
+          <div className="document-viewer__content">{content && this.renderDocument(content)}</div>
+        )}
+      </div>
+    );
+  }
+}
+
+export default DocumentViewer;