add initial marp implementation with sample content and build configuration

node_modules/mathjax-full/ts/output/chtml/Usage.ts

@@ -0,0 +1,76 @@
+/*************************************************************
+ *
+ *  Copyright (c) 2021-2022 The MathJax Consortium
+ *
+ *  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.
+ */
+
+/**
+ * @fileoverview  Keeps track of usage of font characters and wrappers
+ *
+ * @author dpvc@mathjax.org (Davide Cervone)
+ */
+
+/**
+ * Class used for tracking usage of font characters or wrappers
+ */
+export class Usage<T> {
+
+  /**
+   * The used items.
+   */
+  protected used: Set<string> = new Set<string>();
+
+  /**
+   * The items marked as used since last update.
+   */
+  protected needsUpdate: T[] = [];
+
+  /**
+   * @param {T} item   The item that has been used
+   */
+  public add(item: T) {
+    const name = JSON.stringify(item);
+    if (!this.used.has(name)) {
+      this.needsUpdate.push(item);
+    }
+    this.used.add(name);
+  }
+
+  /**
+   * @param {T} item     The item to check for being used
+   * @return {boolean}   True if the item has been used
+   */
+  public has(item: T): boolean {
+    return this.used.has(JSON.stringify(item));
+  }
+
+  /**
+   * Clear the usage information
+   */
+  public clear() {
+    this.used.clear();
+    this.needsUpdate = [];
+  }
+
+  /**
+   * Get the items marked as used since the last update.
+   */
+  public update() {
+    const update = this.needsUpdate;
+    this.needsUpdate = [];
+    return update;
+  }
+
+}
+