level-hooks - npm Package Compare versions

Comparing version 1.0.0 to 1.0.1

package.json

 {
   "name": "level-hooks",
   "description": "pre/post hooks for leveldb",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "homepage": "https://github.com/dominictarr/level-hooks",
@@ -6,0 +6,0 @@ "repository": {

README.md

 # Pre/Post hooks for leveldb
 
+Intercept put/delete/batch operations on levelup.
+
+``` js
+var levelup   = require('levelup')
+var timestamp = require('monotonic-timestamp')
+var hooks     = require('level-hooks')
+
+levelup(file, {createIfMissing: true}, function (err, db) {
+
+  //install hooks onto db.
+  hooks()(db)
+
+  db.hooks.pre(function (batch) {
+
+    //batch is the same format as the arguments to db.batch.
+    //it may be mutated like this to atomically add operations.
+    
+    //example, add a log to record every put operation.
+    batch.forEach(function (e) {
+
+      if(!/~log-/.test(e.key.toString())
+        batch.push({type: 'put', key: '~log-'+timestamp()+'-'+e.type, value: e.key})
+
+    })
+
+    //you can also remove elements.
+    //if there is only one element,
+    //hooks will turn it into an put/del operation, 
+    //not use the batch function.
+
+  })
+
+  //add a hook that responds after an operation has completed.
+
+  //same pattern as the an element in the batch array.
+  db.hooks.post(function (err, ch) {
+    console.log(ch)
+    //{type: 'put'|'del', key: ..., value: ...}
+  })
+
+
+})
+
+```
+
+Used by [map-reduce](https://github.com/dominictarr/map-reduce) 
+to make map-reduce durable across crashes!

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Total package byte prevSize

9471

increased by14.33%

Number of lines in readme file

50

increased by1566.67%

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