#61 added new file.utils.ts for local and remote data reads

src/utils/file.utils.ts

@@ -0,0 +1,26 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import * as config from '../config';
+import {Logger, LogLevel} from '../logger';
+import {window} from 'vscode';
+
+const logger: Logger = new Logger(`file.utils:`, config.logLevel);
+
+/**
+ * Reads local data file or fetches public data source data.
+ * @param dataFilePath Data file path or public data source url.
+ * @param encoding Data file encoding: 'utf8' for text data files, null for binary data reads.
+ */
+export function readDataFile(dataFilePath: string, encoding:string = null): any {
+  let data: any;
+  logger.debug('readDataFile(): ', dataFilePath);
+  if (!dataFilePath.startsWith('http://') && !dataFilePath.startsWith('https://')) {
+    // read local data file via fs read file api
+    // TODO: change this to read data async later
+    data = fs.readFileSync(dataFilePath, encoding);
+  } else {
+    // TODO: fetch remote data with https://github.com/d3/d3-fetch
+    data = '';
+  }
+  return data;
+}