README.md

@@ -336,15 +336,33 @@ If you put more stuff in it, then items will fall out.
 
 * `keys()`
 
-    Return a generator yielding the keys in the cache.
+    Return a generator yielding the keys in the cache, in order from most
+    recently used to least recently used.
+
+* `rkeys()`
+
+    Return a generator yielding the keys in the cache, in order from least
+    recently used to most recently used.
 
 * `values()`
 
-    Return a generator yielding the values in the cache.
+    Return a generator yielding the values in the cache, in order from most
+    recently used to least recently used.
+
+* `rvalues()`
+
+    Return a generator yielding the values in the cache, in order from
+    least recently used to most recently used.
 
 * `entries()`
 
-    Return a generator yielding `[key, value]` pairs.
+    Return a generator yielding `[key, value]` pairs, in order from most
+    recently used to least recently used.
+
+* `rentries()`
+
+    Return a generator yielding `[key, value]` pairs, in order from least
+    recently used to most recently used.
 
 * `find(fn, [getOptions])`
 

index.js

@@ -243,46 +243,74 @@ class LRUCache {
 
   *indexes ({ allowStale = this.allowStale } = {}) {
     if (this.size) {
-      for (let i = this.tail; true; i = this.prev[i]) {
+      for (let i = this.tail, j; true; ) {
+        j = i === this.head
         if (allowStale || !this.isStale(i)) {
           yield i
         }
-        if (i === this.head) {
+        // either head now, or WAS head and head was deleted
+        if (i === this.head || j && !this.isValidIndex(i)) {
           break
+        } else {
+          i = this.prev[i]
         }
       }
     }
   }
+
   *rindexes ({ allowStale = this.allowStale } = {}) {
     if (this.size) {
-      for (let i = this.head; true; i = this.next[i]) {
+      for (let i = this.head, j; true; ) {
+        j = i === this.tail
         if (allowStale || !this.isStale(i)) {
           yield i
         }
-        if (i === this.tail) {
+        // either the tail now, or WAS the tail, and deleted
+        if (i === this.tail || j && !this.isValidIndex(i)) {
           break
+        } else {
+          i = this.next[i]
         }
       }
     }
   }
 
+  isValidIndex (index) {
+    return this.keyMap.get(this.keyList[index]) === index
+  }
+
   *entries () {
     for (const i of this.indexes()) {
       yield [this.keyList[i], this.valList[i]]
     }
   }
+  *rentries () {
+    for (const i of this.rindexes()) {
+      yield [this.keyList[i], this.valList[i]]
+    }
+  }
 
   *keys () {
     for (const i of this.indexes()) {
       yield this.keyList[i]
     }
   }
+  *rkeys () {
+    for (const i of this.rindexes()) {
+      yield this.keyList[i]
+    }
+  }
 
   *values () {
     for (const i of this.indexes()) {
       yield this.valList[i]
     }
   }
+  *rvalues () {
+    for (const i of this.rindexes()) {
+      yield this.valList[i]
+    }
+  }
 
   [Symbol.iterator] () {
     return this.entries()
@@ -315,16 +343,12 @@ class LRUCache {
 
   purgeStale () {
     let deleted = false
-    const toDelete = []
     for (const i of this.rindexes({ allowStale: true })) {
       if (this.isStale(i)) {
-        toDelete.push(this.keyList[i])
+        this.delete(this.keyList[i])
         deleted = true
       }
     }
-    for (const k of toDelete) {
-      this.delete(k)
-    }
     return deleted
   }