dataloader - npm Package Compare versions

Comparing version 1.0.0 to 1.1.0

dist/index.js

@@ -15,3 +15,4 @@
 
-// Optionally turn off batching or caching.
+// Optionally turn off batching or caching or provide a cache key function or a
+// custom cache instance.
 Object.defineProperty(exports, '__esModule', {
@@ -26,3 +27,3 @@ value: true
 /**
- A `DataLoader` creates a public API for loading data from a particular
+ * A `DataLoader` creates a public API for loading data from a particular
  * data back-end with unique keys such as the `id` column of a SQL table or
@@ -46,3 +47,3 @@ * document name in a MongoDB database, given a batch loading function.
     this._options = options;
-    this._promiseCache = new Map();
+    this._promiseCache = options && options.cacheMap || new Map();
     this._queue = [];
@@ -92,6 +93,11 @@ }
       var shouldCache = !options || options.cache !== false;
+      var cacheKeyFn = options && options.cacheKeyFn;
+      var cacheKey = cacheKeyFn ? cacheKeyFn(key) : key;
 
       // If caching and there is a cache-hit, return cached Promise.
-      if (shouldCache && this._promiseCache.has(key)) {
-        return this._promiseCache.get(key);
+      if (shouldCache) {
+        var cachedPromise = this._promiseCache.get(cacheKey);
+        if (cachedPromise) {
+          return cachedPromise;
+        }
       }
@@ -101,9 +107,9 @@
       var promise = new Promise(function (resolve, reject) {
-
-        // Enqueue this Promise to be dispatched, and determine if a new dispatch
-        // needs to be created: if this is the first enqueue upon an empty queue.
-        var needsDispatch = _this._queue.length === 0;
+        // Enqueue this Promise to be dispatched.
         _this._queue.push({ key: key, resolve: resolve, reject: reject });
 
-        if (needsDispatch) {
+        // Determine if a dispatch of this queue should be scheduled.
+        // A single dispatch should be scheduled per queue at the time when the
+        // queue changes from "empty" to "full".
+        if (_this._queue.length === 1) {
           if (shouldBatch) {
@@ -123,3 +129,3 @@ // If batching, schedule a task to dispatch the queue.
       if (shouldCache) {
-        this._promiseCache.set(key, promise);
+        this._promiseCache.set(cacheKey, promise);
       }
@@ -163,3 +169,5 @@
     value: function clear(key) {
-      this._promiseCache['delete'](key);
+      var cacheKeyFn = this._options && this._options.cacheKeyFn;
+      var cacheKey = cacheKeyFn ? cacheKeyFn(key) : key;
+      this._promiseCache['delete'](cacheKey);
       return this;
@@ -166,0 +174,0 @@ }

package.json

 {
   "name": "dataloader",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "A data loading utility to reduce requests to a backend via batching and caching.",
@@ -33,3 +33,3 @@ "contributors": [
     "preversion": ". ./resources/checkgit.sh && npm test",
-    "_prepublish": ". ./resources/prepublish.sh"
+    "prepublish": ". ./resources/prepublish.sh"
   },
@@ -46,12 +46,12 @@ "files": [
     "babel-core": "5.8.22",
-    "babel-eslint": "4.0.10",
-    "chai": "3.2.0",
-    "coveralls": "2.11.3",
-    "eslint": "1.1.0",
-    "eslint-plugin-babel": "^2.1.1",
-    "flow-bin": "0.14.0",
+    "babel-eslint": "4.1.6",
+    "chai": "3.4.1",
+    "coveralls": "2.11.6",
+    "eslint": "1.10.3",
+    "eslint-plugin-babel": "2.2.0",
+    "flow-bin": "0.20.1",
     "isparta": "3.0.3",
-    "mocha": "2.2.5",
-    "sane": "1.1.3"
+    "mocha": "2.3.4",
+    "sane": "1.3.0"
   }
 }

README.md

@@ -31,4 +31,5 @@ # DataLoader
 DataLoader assumes a JavaScript environment with global ES6 `Promise` and `Map`
-classes, available in the recent versions of node.js or when using [babel][].
-If your environment does not have these, provide them before using DataLoader.
+classes, available in the recent versions of node.js or when using
+[babel/polyfill][]. If your environment does not have these, provide them before
+using DataLoader.
 
@@ -45,3 +46,3 @@ ```js
 
-Batching is a not an advanced feature, it's DataLoader's primary feature.
+Batching is not an advanced feature, it's DataLoader's primary feature.
 Create loaders by providing a batch loading function.
@@ -58,4 +59,5 @@
 
-Then load individual values from the loader. In this example, we're illustrating
-two parts of an example application which shows who was invited by whom.
+Then load individual values from the loader. DataLoader will coalesce all
+individual loads which occur within a single frame of execution (a single tick
+of the event loop) and then call your batch function with all requested keys.
 
@@ -155,2 +157,9 @@ ```js
 
+  - *cacheKeyFn*: A function to produce a cache key for a given load key.
+    Defaults to `key => key`. Useful to provide when JavaScript objects are keys
+    and two similarly shaped objects should be considered equivalent.
+
+  - *cacheMap*: An instance of [Map][] (or an object with a similar API) to be
+    used as the underlying cache for this loader. Default `new Map()`.
+
 ##### `load(key)`
@@ -241,6 +250,6 @@
       },
-      type: new GraphQLList(UserType)
-      resolve (user, { first }) => queryLoader.load([
-        'SELECT toID as id FROM friends WHERE fromID=? LIMIT ?', user.id, first
-      ]).then(rows => rows.map(row => userLoader.load(row.friendID)))
+      type: new GraphQLList(UserType),
+      resolve: (user, { first }) => queryLoader.load([
+        'SELECT toID FROM friends WHERE fromID=? LIMIT ?', user.id, first
+      ]).then(rows => rows.map(row => userLoader.load(row.toID)))
     }
@@ -281,2 +290,12 @@ })
 
+## Custom Caches
+
+DataLoader can optionaly be provided a custom Map instance to use as its
+cache. More specifically, any object that implements the methods `get()`,
+`set()`, `delete()` and `clear()` can be provided. This allows for custom Maps
+which implement various [cache algorithms][] to be provided. By default,
+DataLoader uses the standard [Map][] which simply grows until the DataLoader
+is released.
+
+
 ## Common Back-ends
@@ -295,3 +314,3 @@
 var DataLoader = require('dataloader');
-var redis = require("redis");
+var redis = require('redis');
 
@@ -309,3 +328,3 @@ var client = redis.createClient();
   });
-});
+}));
 ```
@@ -368,5 +387,3 @@
     rows => ids.map(
-      id => rows.find(
-        row => row.id === id) || new Error(`Row not found: ${id}`
-      )
+      id => rows.find(row => row.id === id) || new Error(`Row not found: ${id}`)
     )
@@ -405,7 +422,9 @@ );
 [@schrockn]: https://github.com/schrockn
+[Map]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
 [graphql-js]: https://github.com/graphql/graphql-js
+[cache algorithms]: https://en.wikipedia.org/wiki/Cache_algorithms
 [express]: http://expressjs.com/
-[babel]: http://babeljs.io/
+[babel/polyfill]: https://babeljs.io/docs/usage/polyfill/
 [node_redis]: https://github.com/NodeRedis/node_redis
 [nano]: https://github.com/dscape/nano
 [sqlite3]: https://github.com/mapbox/node-sqlite3

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Improved metrics

Total package byte prevSize

28094

increased by5.53%

Lines of code

226

increased by4.15%

Number of lines in readme file

421

increased by4.73%

No dependency changes