1 files changed, 59 insertions, 0 deletions
diff --git a/src/animation/Queue.js b/src/animation/Queue.js
new file mode 100644
index 0000000..14b92b4
--- /dev/null
+++ b/src/animation/Queue.js
@@ -0,0 +1,59 @@
+export default class Queue {
+  constructor () {
+    this._first = null
+    this._last = null
+  }
+
+  push (value) {
+    // An item stores an id and the provided value
+    var item = value.next ? value : { value: value, next: null, prev: null }
+
+    // Deal with the queue being empty or populated
+    if (this._last) {
+      item.prev = this._last
+      this._last.next = item
+      this._last = item
+    } else {
+      this._last = item
+      this._first = item
+    }
+
+    // Update the length and return the current item
+    return item
+  }
+
+  shift () {
+    // Check if we have a value
+    var remove = this._first
+    if (!remove) return null
+
+    // If we do, remove it and relink things
+    this._first = remove.next
+    if (this._first) this._first.prev = null
+    this._last = this._first ? this._last : null
+    return remove.value
+  }
+
+  // Shows us the first item in the list
+  first () {
+    return this._first && this._first.value
+  }
+
+  // Shows us the last item in the list
+  last () {
+    return this._last && this._last.value
+  }
+
+  // Removes the item that was returned from the push
+  remove (item) {
+    // Relink the previous item
+    if (item.prev) item.prev.next = item.next
+    if (item.next) item.next.prev = item.prev
+    if (item === this._last) this._last = item.prev
+    if (item === this._first) this._first = item.next
+
+    // Invalidate item
+    item.prev = null
+    item.next = null
+  }
+}