Smol work on compute graph

js/computation_graph.js

@@ -1,15 +1,33 @@
+let _ALL_NODES = new Map();
 
-class ComputeNode() {
+class ComputeNode {
+    /***
+     * Make a generic compute node.
+     * Adds the node to the global map of nodenames to nodes (for calling from html listeners).
+     *
+     * @param name : Name of the node (string). Must be unique. Must "fit in" a JS string (terminated by single quotes).
+     */
     constructor(name) {
+        if (_ALL_NODES.has(name)) {
+            throw 'Duplicate node name: ' + name;
+        }
+        _ALL_NODES.set(name, this)
         this.inputs = [];
         this.children = [];
         this.value = 0;
         this.compute_func = null;
         this.callback_func = null;
         this.name = name;
+        this.update_task = null;
+        this.update_time = Date.now();
     }
 
-    update() {
+    update(timestamp) {
+        if (timestamp < this.update_time) {
+            return;
+        }
+        this.update_time = timestamp;
+
         let value_map = Map();
         for (const input of this.inputs) {
             value_map.set(input.name, input.get_value());
@@ -25,3 +43,38 @@ class ComputeNode() {
         return this.value
     }
 }
+
+/***
+ * Schedule a ComputeNode to be updated.
+ *
+ * @param node_name : ComputeNode name to schedule an update for.
+ */
+function calcSchedule(node_name) {
+    node = _ALL_NODES.get(node_name);
+    if (node.update_task !== null) {
+        clearTimeout(node.update_task);
+    }
+    node.update_task = setTimeout(function() {
+        const timestamp = Date.now();
+        node.update(timestamp);
+        node.update_task = null;
+    }, 500);
+}
+
+/***
+ * Node for getting an item's stats from an item input field.
+ */
+class ItemStats extends ComputeNode {
+    /***
+     * Make an item stat pulling compute node.
+     *
+     * @param name: Name of this node.
+     * @oaram item_input_field: Input field (html element) to listen for item names from.
+     */
+    constructor(name, item_input_field) {
+        super(name);
+        this.input_field.setAttribute("onInput", "calcSchedule('"+name+"');");
+        this.input_field = item_input_field;
+    }
+}
+

js/sq2builder.js

@@ -256,7 +256,7 @@ function decodeBuild(url_tag) {
     }
 }
 
-/*  Stores the entire build in a string using B64 encryption and adds it to the URL.
+/*  Stores the entire build in a string using B64 encoding and adds it to the URL.
 */
 function encodeBuild() {