hyperbee - npm Package Compare versions

Comparing version 2.9.2 to 2.10.0

index.js

@@ -7,2 +7,3 @@ const codecs = require('codecs')
 const ReadyResource = require('ready-resource')
+const debounce = require('debounceify')
 
@@ -297,3 +298,6 @@ const RangeIterator = require('./iterators/range')
     this._onappendBound = this._view ? null : this._onappend.bind(this)
+    this._ontruncateBound = this._view ? null : this._ontruncate.bind(this)
     this._watchers = this._onappendBound ? [] : null
+    this._entryWatchers = this._onappendBound ? [] : null
+
     this._batches = []
@@ -303,3 +307,3 @@
       this.core.on('append', this._onappendBound)
-      if (this.core.isAutobase) this.core.on('truncate', this._onappendBound)
+      this.core.on('truncate', this._ontruncateBound)
     }
@@ -404,2 +408,16 @@
 
+  async getAndWatch (key) {
+    if (!this._watchers) throw new Error('Can only watch the main bee instance')
+
+    const watcher = new EntryWatcher(this, key)
+    await watcher._debouncedUpdate()
+
+    if (this.closing) {
+      await watcher.close()
+      throw new Error('Bee closed')
+    }
+
+    return watcher
+  }
+
   _onappend () {
@@ -409,4 +427,18 @@ for (const watcher of this._watchers) {
     }
+
+    for (const watcher of this._entryWatchers) {
+      watcher._onappend()
+    }
   }
 
+  _ontruncate () {
+    for (const watcher of this._watchers) {
+      watcher._ontruncate()
+    }
+
+    for (const watcher of this._entryWatchers) {
+      watcher._ontruncate()
+    }
+  }
+
   _makeSnapshot () {
@@ -469,3 +501,3 @@ // TODO: better if we could encapsulate this in hypercore in the future
       this.core.off('append', this._onappendBound)
-      if (this.core.isAutobase) this.core.off('truncate', this._onappendBound)
+      this.core.off('truncate', this._ontruncateBound)
 
@@ -477,2 +509,8 @@ while (this._watchers.length) {
 
+    if (this._entryWatchers) {
+      while (this._entryWatchers.length) {
+        await this._entryWatchers[this._entryWatchers.length - 1].close()
+      }
+    }
+
     while (this._batches.length) {
@@ -900,2 +938,60 @@ await this._batches[this._batches.length - 1].close()
 
+class EntryWatcher extends ReadyResource {
+  constructor (bee, key) {
+    super()
+
+    this.index = bee._entryWatchers.push(this) - 1
+    this.bee = bee
+
+    this.key = key
+    this.node = null
+
+    this._forceUpdate = false
+    this._debouncedUpdate = debounce(this._processUpdate.bind(this))
+  }
+
+  _close () {
+    const top = this.bee._entryWatchers.pop()
+    if (top !== this) {
+      top.index = this.index
+      this.bee._entryWatchers[top.index] = top
+    }
+  }
+
+  _onappend () {
+    this._debouncedUpdate()
+  }
+
+  _ontruncate () {
+    this._forceUpdate = true
+    this._debouncedUpdate()
+  }
+
+  async _processUpdate () {
+    const force = this._forceUpdate
+    this._forceUpdate = false
+
+    let newNode
+    try {
+      newNode = await this.bee.get(this.key)
+    } catch (e) {
+      if (e.code === 'SNAPSHOT_NOT_AVAILABLE') {
+        // There was a truncate event before the get resolved
+        // So this handler will run again anyway
+        return
+      } else if (this.bee.closing) {
+        this.close().catch(safetyCatch)
+        return
+      }
+      this.emit('error', e)
+      return
+    }
+
+    if (force || newNode?.seq !== this.node?.seq) {
+      this.node = newNode
+      this.emit('update')
+    }
+  }
+}
+
 class Watcher extends ReadyResource {
@@ -934,2 +1030,6 @@ constructor (bee, range, opts = {}) {
 
+  _ontruncate () {
+    if (this.core.isAutobase) this._onappend()
+  }
+
   _onappend () {
@@ -936,0 +1036,0 @@ // TODO: this is a light hack / fix for non-sparse session reporting .length's inside batches

package.json

 {
   "name": "hyperbee",
-  "version": "2.9.2",
+  "version": "2.10.0",
   "description": "An append-only B-tree running on a Hypercore.",
@@ -14,2 +14,3 @@ "main": "index.js",
     "codecs": "^3.0.0",
+    "debounceify": "^1.0.0",
     "mutexify": "^1.4.0",
@@ -16,0 +17,0 @@ "protocol-buffers-encodings": "^1.2.0",

README.md

@@ -262,2 +262,12 @@ # Hyperbee 🐝
 
+#### `const entryWatcher = await db.getAndWatch(key)`
+
+Returns a watcher which listens to changes on the given key.
+
+`entryWatcher.node` contains the current entry in the same format as the result of `bee.get(key)`,  and will be updated as it changes.
+
+You can listen to `entryWatcher.on('update')` to be notified when the value of node has changed.
+
+Call `await watcher.close()` to stop the watcher.
+
 #### `const watcher = db.watch([range])`
@@ -264,0 +274,0 @@

New alerts

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License

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Found 1 instance in 1 package

Fixed alerts

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License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

87200

increased by3.07%

Lines of code

2436

increased by3.4%

Number of lines in readme file

348

increased by2.96%

Worsened metrics

Dependency count

8

increased by14.29%

Dependency changes

• + Addeddebounceify@^1.0.0

• + Addeddebounceify@1.1.0(transitive)