Guards around setting max/maxAge to non-numbers

Close #136

README.md

@@ -18,8 +18,8 @@ var LRU = require("lru-cache")
               , length: function (n, key) { return n * 2 + key.length }
               , dispose: function (key, n) { n.close() }
               , maxAge: 1000 * 60 * 60 }
-  , cache = LRU(options)
-  , otherCache = LRU(50) // sets just the max size
+  , cache = new LRU(options)
+  , otherCache = new LRU(50) // sets just the max size
 
 cache.set("key", "value")
 cache.get("key") // "value"
@@ -49,10 +49,13 @@ away.
 * `max` The maximum size of the cache, checked by applying the length
   function to all values in the cache.  Not setting this is kind of
   silly, since that's the whole purpose of this lib, but it defaults
-  to `Infinity`.
+  to `Infinity`.  Setting it to a non-number or negative number will
+  throw a `TypeError`.  Setting it to 0 makes it be `Infinity`.
 * `maxAge` Maximum age in ms.  Items are not pro-actively pruned out
   as they age, but if you try to get an item that is too old, it'll
   drop it and return undefined instead of giving it to you.
+  Setting this to a negative value will make everything seem old!
+  Setting it to a non-number will throw a `TypeError`.
 * `length` Function that is used to calculate the length of stored
   items.  If you're storing strings or buffers, then you probably want
   to do something like `function(n, key){return n.length}`.  The default is

index.js

@@ -31,16 +31,16 @@ class LRUCache {
     if (!options)
       options = {}
 
-    const max = this[MAX] = options.max
+    if (options.max && (typeof options.max !== 'number' || options.max < 0))
+      throw new TypeError('max must be a non-negative number')
     // Kind of weird to have a default max of Infinity, but oh well.
-    if (!max ||
-        !(typeof max === 'number') ||
-        max <= 0)
-      this[MAX] = Infinity
+    const max = this[MAX] = options.max || Infinity
 
     const lc = options.length || naiveLength
     this[LENGTH_CALCULATOR] = (typeof lc !== 'function') ? naiveLength : lc
     this[ALLOW_STALE] = options.stale || false
+    if (options.maxAge && typeof options.maxAge !== 'number')
+      throw new TypeError('maxAge must be a number')
     this[MAX_AGE] = options.maxAge || 0
     this[DISPOSE] = options.dispose
     this[NO_DISPOSE_ON_SET] = options.noDisposeOnSet || false
@@ -49,10 +49,10 @@ class LRUCache {
 
   // resize the cache when the max changes.
   set max (mL) {
-    if (!mL || !(typeof mL === 'number') || mL <= 0)
-      mL = Infinity
+    if (typeof mL !== 'number' || mL < 0)
+      throw new TypeError('max must be a non-negative number')
 
-    this[MAX] = mL
+    this[MAX] = mL || Infinity
     trim(this)
   }
   get max () {
@@ -67,8 +67,8 @@ class LRUCache {
   }
 
   set maxAge (mA) {
-    if (!mA || !(typeof mA === 'number') || mA < 0)
-      mA = 0
+    if (typeof mA !== 'number')
+      throw new TypeError('maxAge must be a non-negative number')
 
     this[MAX_AGE] = mA
     trim(this)

test/basic.js

@@ -63,7 +63,7 @@ test('max', function (t) {
   }
 
   // now remove the max restriction, and try again.
-  cache.max = 'hello'
+  cache.max = 0
   for (i = 0; i < 100; i++) cache.set(i, i)
   t.equal(cache.length, 100)
   for (i = 0; i < 100; i++) {
@@ -520,11 +520,6 @@ test('maxAge on list, cleared in forEach', function (t) {
   // hacky.  make it seem older.
   l.dumpLru().head.value.now = Date.now() - 100000
 
-  // setting maxAge to invalid values does nothing.
-  t.equal(l.maxAge, 0)
-  l.maxAge = -100
-  t.equal(l.maxAge, 0)
-  l.maxAge = {}
   t.equal(l.maxAge, 0)
 
   l.maxAge = 1
@@ -539,3 +534,11 @@ test('maxAge on list, cleared in forEach', function (t) {
 
   t.end()
 })
+
+test('bad max/maxAge options', t => {
+  t.throws(() => new LRU({ maxAge: true }), 'maxAge must be a number')
+  t.throws(() => { new LRU().maxAge = 'foo' }, 'maxAge must be a number')
+  t.throws(() => new LRU({ max: true }), 'max must be a non-negative number')
+  t.throws(() => { new LRU().max = 'foo' }, 'max must be a non-negative number')
+  t.end()
+})