#63 add maxKeys option

daluf · daluf · commit 579e5bb20482 · 2019-08-23T14:25:08.000+02:00
diff --git a/README.md b/README.md
@@ -52,7 +52,8 @@ const myCache = new NodeCache();
 _Here's a [simple code example](https://runkit.com/mpneuried/useclones-example-83) showing the different behavior_
 - `deleteOnExpire`: *(default: `true`)* whether variables will be deleted automatically when they expire.
 If `true` the variable will be deleted. If `false` the variable will remain. You are encouraged to handle the variable upon the event `expired` by yourself.
-- `enableLegacyCallbacks`: *(default: `false`)* re-enables the usage of callbacks instead of sync functions. adds an additional `cb` argument to each function which resolves to `(err, result)`. will be removed in node-cache v6.x.
+- `enableLegacyCallbacks`: *(default: `false`)* re-enables the usage of callbacks instead of sync functions. Adds an additional `cb` argument to each function which resolves to `(err, result)`. will be removed in node-cache v6.x.
+- `maxKeys`: *(default: `-1`)* specifies a maximum amount of keys that can be stored in the cache. If a new item is set and the cache is full, an error is thrown and the key will not be saved in the cache. -1 disables the key limit.
 
 ```js
 const NodeCache = require( "node-cache" );
diff --git a/_src/lib/node_cache.coffee b/_src/lib/node_cache.coffee
@@ -30,11 +30,13 @@ module.exports = class NodeCache extends EventEmitter
 			deleteOnExpire: true
 			# enable legacy callbacks
 			enableLegacyCallbacks: false
+			# max amount of keys that are being stored
+			maxKeys: -1
 		, @options )
 
 		# generate functions with callbacks (legacy)
 		if (@options.enableLegacyCallbacks)
-			console.warn("WARNING! Callback legacy support will drop in v6.x")
+			console.warn("WARNING! Callback legacy support will drop in node-cache v6.x")
 			[
 				"get",
 				"mget",
@@ -164,6 +166,11 @@ module.exports = class NodeCache extends EventEmitter
 	#       console.log( err, success )
 	#
 	set: ( key, value, ttl )=>
+		# check if cache is overflowing
+		if (@stats.keys >= @options.maxKeys && @options.maxKeys > -1)
+			_err = @_error( "ECACHEFULL" )
+			throw _err
+
 		# force the data to string
 		if @options.forceString and not typeof value is "string"
 			value = JSON.stringify( value )
@@ -599,5 +606,6 @@ module.exports = class NodeCache extends EventEmitter
 
 	_ERRORS:
 		"ENOTFOUND": "Key `__key` not found"
+		"ECACHEFULL": "Cache max key size exceeded"
 		"EKEYTYPE": "The key argument has to be of type `string` or `number`. Found: `__key`"
 		"EKEYSTYPE": "The keys argument has to be an array."
