Cache all module data

Summary:
We used to only cache the `dependencies` and `name` of a Module but we were actually accessing two more fields (async dependencies and the `isHaste` field) which meant we were always reading every single file from disk. In D2644383 I noticed that but realized that the Promise was cached, meaning we would read every file once *per instance* and I didn't think about cross-instance reads over time. My initial version added more caching (but also missed the `isHaste` field) but then I got rid of the cache call for `dependencies`. So my change from before didn't make anything worse but it also didn't make anything better. This change now caches everything until the contents of the file actually changes.

public

Reviewed By: martinbigio

Differential Revision: D2831569

fb-gh-sync-id: 74081abc0ce3ca96b4e56c3c9b6d24aa84f7496c

react-packager/src/DependencyResolver/Module.js

@@ -31,7 +31,11 @@ class Module {
   }
 
   isHaste() {
-    return this.read().then(data => !!data.id);
+    return this._cache.get(
+      this.path,
+      'isHaste',
+      () => this.read().then(data => !!data.id)
+    );
   }
 
   getName() {
@@ -67,11 +71,19 @@ class Module {
   }
 
   getDependencies() {
-    return this.read().then(data => data.dependencies);
+    return this._cache.get(
+      this.path,
+      'dependencies',
+      () => this.read().then(data => data.dependencies)
+    );
   }
 
   getAsyncDependencies() {
-    return this.read().then(data => data.asyncDependencies);
+    return this._cache.get(
+      this.path,
+      'asyncDependencies',
+      () => this.read().then(data => data.asyncDependencies)
+    );
   }
 
   invalidate() {