Improve: Support null ttl to disable caching

README.md

@@ -40,6 +40,13 @@ Record
   .exec(function(err, aggResults) {
     ...
   });
+
+Record
+  .find({})
+  .cache(null) // Explicitly passing in null will not cache the results.
+  .exec(function(err, records) {
+    ...
+  });
 ```
 
 You can also pass a custom key into the `.cache()` method, which you can then use later to clear the cached content.

src/cache.js

@@ -12,6 +12,7 @@ Cache.prototype.get = function(key, cb = noop) {
 };
 
 Cache.prototype.set = function(key, value, ttl, cb = noop) {
+  if (ttl === null) return cb();
   if (ttl === 0) ttl = -1;
   return this._cache.set(key, value, ttl, cb);
 };

src/extend-aggregate.js

@@ -28,7 +28,7 @@ module.exports = function(mongoose, cache) {
 
       return new Promise((resolve, reject) => {
         cache.get(key, (err, cachedResults) => { //eslint-disable-line handle-callback-err
-          if (cachedResults) {
+          if (cachedResults != null && ttl !== null) {
             callback(null, cachedResults);
             return resolve(cachedResults);
           }

src/extend-query.js

@@ -23,7 +23,7 @@ module.exports = function(mongoose, cache) {
 
     return new Promise((resolve, reject) => {
       cache.get(key, (err, cachedResults) => { //eslint-disable-line handle-callback-err
-        if (cachedResults != null) {
+        if (cachedResults != null && ttl !== null) {
           if (isCount) {
             callback(null, cachedResults);
             return resolve(cachedResults);

test/index.js

@@ -80,7 +80,7 @@ describe('cachegoose', () => {
     cachedRes.length.should.equal(10);
   });
 
-  it('should not cache the same query w/out a ttl defined', async () => {
+  it('should not cache the same query w/out a cachegoose invoking', async () => {
     const res = await getAll(60);
     res.length.should.equal(10);
 
@@ -90,6 +90,24 @@ describe('cachegoose', () => {
     nonCachedResponse.length.should.equal(20);
   });
 
+  it('should not cache query w/out a ttl defined', async () => {
+    const res = await getAll(null);
+    res.length.should.equal(10);
+
+    await generate(10);
+    const cachedRes = await getAll(null);
+    cachedRes.length.should.equal(20);
+  });
+
+  it('should clear cache w/out a ttl defined', async () => {
+    const res = await getAll(60);
+    res.length.should.equal(10);
+
+    await generate(10);
+    const cachedRes = await getAll(null);
+    cachedRes.length.should.equal(20);
+  });
+
   it('should return a Mongoose model from cached and non-cached results', (done) => {
     getAll(60, (err, res) => {
       if (err) return done(err);