memoize-cache - npm Package Compare versions

Comparing version 0.1.0 to 0.1.1

package.json

 {
   "name": "memoize-cache",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "A cache support for memoized functions",
@@ -31,4 +31,5 @@ "main": "index.js",
   "dependencies": {
+    "md5-o-matic": "^0.1.1",
     "sizeof": "^1.0.0"
   }
 }

ram-cache.js

 var sizeof = require('sizeof');
-
+var Heap = require('./heap');
+var md5omatic = require('md5-o-matic');
 /*
@@ -9,7 +10,20 @@
 
+function sortByLessPopular(a, b) {
+  return a.times < b.times;
+}
+
+function sortByOldest(a, b) {
+  return a.ts < b.ts;
+}
+
+function removeByKey(key) {
+  return function (item) {
+    return item.key === key;
+  };
+}
+
 function Cache(opts) {
   opts = opts || {};
 
-  this._cache = {}; // key, value
-  this._cacheKeys = []; // sorted by time {ts: xxx, key: xxx} new ones first
+  this.reset();
 
@@ -21,14 +35,29 @@ this._getCacheKey = opts.key || function () { return '_default'; };
 
-Cache.prototype.push = function cache_push(args, output) {
+Cache.prototype.getCacheKey = function cache_getCacheKey(args) {
   var k = this._getCacheKey.apply(undefined, args);
   if (typeof k !== 'string') {
-    k = JSON.stringify(k);
+    k = md5omatic(JSON.stringify(k));
   }
+  return k;
+};
+
+Cache.prototype.push = function cache_push(args, output) {
+  var lru;
+  var k = this.getCacheKey(args);
   if (k in this._cache) return;
+
+  if(this._LRU.size() === this._maxLen) {
+    lru = this._LRU.pop();
+    delete this._cache[lru.key];
+    this._oldest.remove(removeByKey(lru.key));
+  }
+
   this._cache[k] = output;
-  this._cacheKeys.unshift({
+
+  this._LRU.push({key: k, times: 0});
+
+  this._oldest.push({
     key: k,
     ts: Date.now()
   });
-  this._purgeByLen();
 };
@@ -38,32 +67,22 @@
   // remove old entries
-  var maxAge = this._maxAge;
-  var cache = this._cache;
+  var oldest;
+  var now = Date.now();
 
-  var now = Date.now();
-  this._cacheKeys = this._cacheKeys.filter(function (item) {
-    if (item.ts + maxAge < now ) {
-      delete cache[item.key];
-      return false;
+  while (this._oldest.size()) {
+    oldest = this._oldest.pop();
+    if (oldest.ts + this._maxAge < now) {
+      delete this._cache[oldest.key];
+      this._LRU.remove(removeByKey(oldest.key));
     }
-    return true;
-  });
+    else {
+      this._oldest.push(oldest);
+      break;
+    }
+  }
 };
 
-Cache.prototype._purgeByLen = function cache__purgeByLen() {
-  // remove old entries
-  var maxLen = this._maxLen;
-  var cache = this._cache;
-
-  // trim cache
-  var keysToRemove = this._cacheKeys.slice(maxLen, Infinity);
-  keysToRemove.forEach(function (item) {
-    var k = item.key;
-    delete cache[k];
-  });
-  this._cacheKeys = this._cacheKeys.slice(0, maxLen);
-};
-
 Cache.prototype.reset = function cache_reset() {
   this._cache = {}; // key, value
-  this._cacheKeys = []; // sorted by time {ts: xxx, key: xxx}
+  this._LRU = new Heap(sortByLessPopular);
+  this._oldest = new Heap(sortByOldest);
 };
@@ -74,13 +93,15 @@
     cached = false,
+    lru,
     key;
   try {
     this._purgeByAge(); // purge stale cache entries
-    key = this._getCacheKey.apply(undefined, args);
-    if (typeof key !== 'string') {
-      key = JSON.stringify(key);
-    }
 
+    key = this.getCacheKey(args);
+
     if (key in this._cache) {
       cached = true;
       hit = this._cache[key]; // cache hit!
+      lru = this._LRU.remove(removeByKey(key));
+      lru.times++;
+      this._LRU.push(lru);
     }
@@ -104,5 +125,5 @@ }
 Cache.prototype.len = function cache_len() {
-  return this._cacheKeys.length;
+  return this._LRU.size();
 };
 
 module.exports = Cache;

README.md

 memoize-cache
 =============
-A configurable cache support for memoized functions.
+A configurable cache support for memoized functions. It is lightweight so it can run in the browser without any problem.
 
@@ -12,8 +12,10 @@ A note about the API
 The constructor takes an option object with 3 optional attributes:
-* key: a function used to extract the cache key (used in the push and query method for storing, retrieving the cached value). The key returned should be a string or it will be converted to JSON. Default: a function returning a fixed key.
+* key: a function used to extract the cache key (used in the push and query method for storing, retrieving the cached value). The key returned should be a string or it will be converted to JSON and then md5. Default: a function returning a fixed key.
 * maxAge: the maximum age of the item stored in the cache (in ms). Default: Infinity
-* maxLen: the maximum number of items stored in the cache. Default: Infinity
+* maxLen: the maximum number of items stored in the cache. Default: Infinity. Cache items will be purged using an LRU algorithm
 
 Example:
 ```js
+var Cache = require('memoize-cache/ram-cache'); // or require('memoize-cache').ramCache;
+
 // no values, uses always the same key for store any value
@@ -20,0 +22,0 @@ var cache = new Cache();

tests/ram-cache.spec.js

@@ -6,2 +6,9 @@ var assert = require('chai').assert;
 
+  it('must translate args to key', function () {
+    var cache = new Cache({key: function (n) {return n;}});
+    assert.equal(cache.getCacheKey(['1']), '1');
+    assert.equal(cache.getCacheKey([1]), 'c4ca4238a0b923820dcc509a6f75849b');
+    assert.equal(cache.getCacheKey([{d:1}]), 'dc6f789c90af7a7f8156af120f33e3be');
+  });
+
   it('must configure cache: default key', function (done) {
@@ -72,3 +79,3 @@ var cache = new Cache();
       assert.equal(res1.cached, true);
-      assert.equal(res1.key, '[1,2]');
+      assert.equal(res1.key, 'f79408e5ca998cd53faf44af31e6eb45');
       assert.equal(res1.hit, 'result1');
@@ -87,3 +94,3 @@ done();
       assert.equal(res1.cached, true);
-      assert.equal(res1.key, '1');
+      assert.equal(res1.key, 'c4ca4238a0b923820dcc509a6f75849b');
       assert.equal(res1.hit, 'result1');
@@ -102,3 +109,3 @@ done();
       assert.equal(res1.cached, true);
-      assert.equal(res1.key, '[1,2]');
+      assert.equal(res1.key, 'f79408e5ca998cd53faf44af31e6eb45');
       assert.equal(res1.hit, 'result1');
@@ -117,3 +124,3 @@ done();
       assert.equal(res1.cached, true);
-      assert.equal(res1.key, '8');
+      assert.equal(res1.key, 'c9f0f895fb98ab9159f51fd0297e236d');
       assert.equal(res1.hit, 'result1');
@@ -131,14 +138,10 @@ done();
       }, maxLen: 2});
-      cache.push([{test: 1}], 'result1');
-      cache.push([{test: 2}], 'result2');
-      cache.push([{test: 3}], 'result3');
+      cache.push([{test: '1'}], 'result1');
+      cache.push([{test: '2'}], 'result2');
     });
 
-    it('must be right size', function () {
-      assert.equal(cache.len(), 2);
-    });
-
-    it('must not be cached (purged)', function (done) {
-      cache.query([{test: 1}], function (err, res1) {
-        assert.equal(res1.cached, false);
+    it('must be on the top of the heap', function (done) {
+      assert.deepEqual(cache._LRU.peek(), {key: '1', times: 0});
+      cache.query([{test: '1'}], function () {
+        assert.deepEqual(cache._LRU.peek(), {key: '2', times: 0});
         done();
@@ -148,18 +151,38 @@ });
 
-    it('must not be cached 1', function (done) {
-      cache.query([{test: 2}], function (err, res2) {
-        assert.equal(res2.cached, true);
-        assert.equal(res2.key, '2');
-        assert.equal(res2.hit, 'result2');
-        done();
+    describe('remove one', function () {
+      beforeEach(function (done) {
+        cache.query([{test: '2'}], function () {
+          cache.push([{test: '3'}], 'result3');
+          done();
+        });
       });
-    });
+      it('must be right size', function () {
+        assert.equal(cache.len(), 2);
+      });
 
-    it('must not be cached 2', function (done) {
-      cache.query([{test: 3}], function (err, res3) {
-        assert.equal(res3.cached, true);
-        assert.equal(res3.key, '3');
-        assert.equal(res3.hit, 'result3');
-        done();
+
+      it('must not be cached (purged)', function (done) {
+        cache.query([{test: '1'}], function (err, res1) {
+          assert.equal(res1.cached, false);
+          done();
+        });
       });
+
+      it('must not be cached 1', function (done) {
+        cache.query([{test: '2'}], function (err, res2) {
+          assert.equal(res2.cached, true);
+          assert.equal(res2.key, '2');
+          assert.equal(res2.hit, 'result2');
+          done();
+        });
+      });
+
+      it('must not be cached 2', function (done) {
+        cache.query([{test: '3'}], function (err, res3) {
+          assert.equal(res3.cached, true);
+          assert.equal(res3.key, '3');
+          assert.equal(res3.hit, 'result3');
+          done();
+        });
+      });
     });
@@ -175,7 +198,7 @@ });
       }, maxAge: 30});
-      cache.push([{test: 1}], 'result1');
+      cache.push([{test: '1'}], 'result1');
     });
 
     it('must be cached', function (done) {
-      cache.query([{test: 1}], function (err, res1) {
+      cache.query([{test: '1'}], function (err, res1) {
         assert.equal(res1.cached, true);
@@ -190,3 +213,3 @@ assert.equal(res1.key, '1');
       setTimeout(function () {
-        cache.query([{test: 1}], function (err, res1) {
+        cache.query([{test: '1'}], function (err, res1) {
           assert.equal(res1.cached, true);
@@ -202,7 +225,13 @@ assert.equal(res1.key, '1');
       setTimeout(function () {
-        cache.query([{test: 1}], function (err, res1) {
+        cache.push([{test: '2'}], 'result2');
+        cache.query([{test: '1'}], function (err, res1) {
           assert.equal(res1.cached, false);
           assert.equal(res1.key, '1');
           assert.isUndefined(res1.hit);
-          done();
+          cache.query([{test: '2'}], function (err, res1) {
+            assert.equal(res1.cached, true);
+            assert.equal(res1.key, '2');
+            assert.equal(res1.hit, 'result2');
+            done();
+          });
         });
@@ -217,3 +246,3 @@ }, 40);
     }});
-    cache.push([{test: 1}], 'result1');
+    cache.push([{test: '1'}], 'result1');
 
@@ -220,0 +249,0 @@ cache.reset();

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Major refactor

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Improved metrics

Total package byte prevSize

22036

increased by70.16%

Number of package files

11

increased by22.22%

Lines of code

559

increased by105.51%

Number of lines in readme file

69

increased by2.99%

Number of medium supply chain risk alerts

0

decreased by-100%

Worsened metrics

Dependency count

2

increased by100%

Dependency changes

• + Addedmd5-o-matic@^0.1.1

• + Addedmd5-o-matic@0.1.1(transitive)