Refactored stock buying/selling code into its own file. Refactored WorkerScript & NetscriptEnvironment into their own Typescript classes. Refactored a ton of code to remove circular dependencies

src/StockMarket/Order.ts

@@ -22,11 +22,26 @@ export class Order {
 
     readonly pos: PositionTypes;
     readonly price: number;
-    readonly shares: number;
+    shares: number;
     readonly stock: Stock;
     readonly type: OrderTypes;
 
     constructor(stk: Stock = new Stock(), shares: number=0, price: number=0, typ: OrderTypes=OrderTypes.LimitBuy, pos: PositionTypes=PositionTypes.Long) {
+        // Validate arguments
+        let invalidArgs: boolean = false;
+        if (typeof shares !== "number" || typeof price !== "number") {
+            invalidArgs = true;
+        }
+        if (isNaN(shares) || isNaN(price)) {
+            invalidArgs = true;
+        }
+        if (!(stk instanceof Stock)) {
+            invalidArgs = true;
+        }
+        if (invalidArgs) {
+            throw new Error(`Invalid constructor paramters for Order`);
+        }
+
         this.stock = stk;
         this.shares = shares;
         this.price = price;