Add belt reader building

src/js/game/components/belt_reader.js

@@ -0,0 +1,40 @@
+import { Component } from "../component";
+import { BaseItem } from "../base_item";
+
+export class BeltReaderComponent extends Component {
+    static getId() {
+        return "BeltReader";
+    }
+
+    duplicateWithoutContents() {
+        return new BeltReaderComponent();
+    }
+
+    constructor() {
+        super();
+
+        /**
+         * Which items went through the reader, we only store the time
+         * @type {Array<number>}
+         */
+        this.lastItemTimes = [];
+
+        /**
+         * Which item passed the reader last
+         * @type {BaseItem}
+         */
+        this.lastItem = null;
+
+        /**
+         * Stores the last throughput we computed
+         * @type {number}
+         */
+        this.lastThroughput = 0;
+
+        /**
+         * Stores when we last computed the throughput
+         * @type {number}
+         */
+        this.lastThroughputComputation = 0;
+    }
+}

src/js/game/components/item_processor.js

@@ -20,6 +20,7 @@ export const enumItemProcessorTypes = {
     painterQuad: "painterQuad",
     hub: "hub",
     filter: "filter",
+    reader: "reader",
 };
 
 /** @enum {string} */