add null logger

src/logging/NullLogger.js

@@ -0,0 +1,47 @@
+/*
+Copyright 2020 Bruno Windels <bruno@windels.cloud>
+
+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 {LogLevel} from "./LogLevel.js";
+
+export class NullLogger {
+    constructor() {
+        this._item = new NullLogItem();
+    }
+
+    wrapLog(_, callback) {
+        callback(this._item);    
+    }
+
+    async export() {
+        return null;
+    }
+
+    get level() {
+        return LogLevel;
+    }
+}
+
+class NullLogItem {
+    wrap(_, callback) {
+        callback(this);
+    }
+    log() {}
+    set() {}
+    anonymize() {}
+
+    get level() {
+        return LogLevel;
+    }
+}