feat: fs-adapter util

packages-node/providence-analytics/src/program/utils/fs-adapter.js

@@ -0,0 +1,27 @@
+import originalNodeFs from 'fs';
+
+/**
+ * Provides access to the file system (fs) which can be the real file system or a mock.
+ */
+class FsAdapter {
+  constructor() {
+    this.fs = originalNodeFs;
+  }
+
+  /**
+   * Call this for mocking or compatibility with non-node environments.
+   * @param {originalNodeFs} fs
+   */
+  setFs(fs) {
+    this.fs = fs;
+  }
+
+  /**
+   * When done testing, call this to restore the real file system.
+   */
+  restoreFs() {
+    this.fs = originalNodeFs;
+  }
+}
+
+export const fsAdapter = new FsAdapter();