Add peekRecord and peekAll, caching records in the store

README.MD

@@ -199,6 +199,13 @@ You will get an array of objects where every mapped relationship will be automat
 ]
 ```
 
+Use `peekAll()` to retrieve all of the records for a given type that are already loaded into the store, without making a network request:
+
+```typescript
+let posts = this.datastore.peekAll(Post);
+```
+
+
 #### Retrieving a Single Record
 
 Use `findRecord()` to retrieve a record by its type and ID:
@@ -219,6 +226,12 @@ this.datastore.findRecord(Post, '1', {
 );
 ```
 
+Use `peekRecord()` to retrieve a record by its type and ID, without making a network request. This will return the record only if it is already present in the store:
+
+```typescript
+let post = this.datastore.peekRecord(Post, '1');
+```
+
 ### Creating, Updating and Deleting 
 
 #### Creating Records

src/services/json-api-datastore.service.ts

@@ -12,6 +12,7 @@ export type ModelType = { new(datastore: JsonApiDatastore, data: any): JsonApiMo
 export class JsonApiDatastore {
 
     private _headers: Headers;
+    private _store: any = {};
 
     constructor(private http: Http) { }
 
@@ -54,6 +55,16 @@ export class JsonApiDatastore {
             .catch((res: any) => this.handleError(res));
     }
 
+    peekRecord(modelType: ModelType, id: string) {
+        let type = Reflect.getMetadata('JsonApiModelConfig', modelType).type;
+        return this._store[type][id];
+    }
+
+    peekAll(modelType: ModelType) {
+        let type = Reflect.getMetadata('JsonApiModelConfig', modelType).type;
+        return _.values(this._store[type]);
+    }
+
     set headers(headers: Headers){
         this._headers = headers;
     }
@@ -95,6 +106,7 @@ export class JsonApiDatastore {
             }
             models.push(model);
         });
+        this.addToStore(models);
         return models;
     }
 
@@ -104,6 +116,7 @@ export class JsonApiDatastore {
         if (body.included) {
             model.syncRelationships(body.data, body.included);
         }
+        this.addToStore(model);
         return model;
     }
 
@@ -155,4 +168,19 @@ export class JsonApiDatastore {
         return encodedStr;
     }
 
+    private addToStore(models: JsonApiModel | JsonApiModel[]) {
+        let model = models instanceof Array ? models[0] : models;
+        let type = Reflect.getMetadata('JsonApiModelConfig', model.constructor).type;
+        if (!this._store[type]) {
+            this._store[type] = {};
+        }
+        let hash = this.fromArrayToHash(models);
+        _.extend(this._store[type], hash);
+    }
+
+    private fromArrayToHash(models: JsonApiModel | JsonApiModel[]) {
+        let modelsArray: JsonApiModel[] = models instanceof Array ? models : [models];
+        return _.indexBy(modelsArray, 'id');
+    }
+
 }