feat: add transformations

Fixes #9

src/transformations/add-log-level.ts

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019 StApps
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+import {LogLevel} from '../logger';
+import {Transformation} from '../transformation';
+
+/**
+ * Transformation that adds the log level to output
+ */
+export class AddLogLevel implements Transformation {
+  /**
+   * Add log level to output
+   *
+   * @param logLevel Log level to add to output
+   * @param output Output to colorize
+   */
+  // tslint:disable-next-line:prefer-function-over-method
+  transform(logLevel: LogLevel, output: string): string {
+    return `[${logLevel}] ${output}`;
+  }
+}