Implement "clear" method in "metro-cache" stores

Reviewed By: rubennorte

Differential Revision: D7628735

fbshipit-source-id: a129bd32f30be968116e0efa065badc6a7d55d51

packages/metro-cache/package.json

@@ -14,6 +14,7 @@
   "dependencies": {
     "jest-serializer": "22.4.3",
     "metro-core": "0.32.0",
-    "mkdirp": "^0.5.1"
+    "mkdirp": "^0.5.1",
+    "rimraf": "^2.5.4"
   }
 }

packages/metro-cache/src/stores/FileStore.js

@@ -13,6 +13,7 @@
 const fs = require('fs');
 const mkdirp = require('mkdirp');
 const path = require('path');
+const rimraf = require('rimraf');
 
 import type {TransformedCode} from 'metro/src/JSTransformer/worker';
 
@@ -27,13 +28,8 @@ class FileStore {
   _root: string;
 
   constructor(options: Options) {
-    const root = options.root;
-
-    for (let i = 0; i < 256; i++) {
-      mkdirp.sync(path.join(root, ('0' + i.toString(16)).slice(-2)));
-    }
-
-    this._root = root;
+    this._root = options.root;
+    this._createDirs();
   }
 
   get(key: Buffer): ?TransformedCode {
@@ -65,6 +61,11 @@ class FileStore {
     fs.writeFileSync(this._getFilePath(key), data);
   }
 
+  clear() {
+    this._removeDirs();
+    this._createDirs();
+  }
+
   _getFilePath(key: Buffer): string {
     return path.join(
       this._root,
@@ -72,6 +73,18 @@ class FileStore {
       key.slice(1).toString('hex'),
     );
   }
+
+  _createDirs() {
+    for (let i = 0; i < 256; i++) {
+      mkdirp.sync(path.join(this._root, ('0' + i.toString(16)).slice(-2)));
+    }
+  }
+
+  _removeDirs() {
+    for (let i = 0; i < 256; i++) {
+      rimraf.sync(path.join(this._root, ('0' + i.toString(16)).slice(-2)));
+    }
+  }
 }
 
 module.exports = FileStore;

packages/metro-cache/src/stores/HttpStore.js

@@ -149,6 +149,10 @@ class HttpStore {
       gzip.end(JSON.stringify(value) || 'null');
     });
   }
+
+  clear() {
+    // Not implemented.
+  }
 }
 
 module.exports = HttpStore;

packages/metro-cache/src/types.flow.js

@@ -13,4 +13,5 @@
 export type CacheStore<T> = {
   get(key: Buffer): ?T | Promise<?T>,
   set(key: Buffer, value: T): void | Promise<void>,
+  clear(): void | Promise<void>,
 };