feat(core): ✨ add Headers module

packages/core/src/modules/Headers.ts

@@ -0,0 +1,62 @@
+/**
+ * @barba/core/modules/headers
+ * <br><br>
+ * ## Manage request Headers.
+ *
+ * @module core/modules/headers
+ * @preferred
+ */
+
+/***/
+
+export class Headers {
+  private _list: HeaderList = new Map([
+    ['x-barba', 'yes'],
+  ]);
+
+  /**
+   * Set a new header
+   */
+  public set(name: string, value: string): IHeaderData {
+    this._list.set(name, value);
+
+    return {
+      name: value
+    };
+  }
+
+  /**
+   * Get a specific header
+   */
+  public get(name: string): string {
+    return this._list.get(name);
+  }
+
+  /**
+   * Get all headers
+   */
+  public all(): HeaderList {
+    return this._list;
+  }
+
+  /**
+   * Check if header exists
+   */
+  public has(name: string): boolean {
+    return this._list.has(name);
+  }
+
+  /**
+   * Delete a header
+   */
+  public delete(name: string): boolean {
+    return this._list.delete(name);
+  }
+
+  /**
+   * Clear all headers
+   */
+  public clear(): void {
+    return this._list.clear();
+  }
+}