OK, fine, draw the map

src/engine/datatypes.ts

@@ -66,6 +66,10 @@ export class Point {
   negate() {
     return new Point(-this.x, -this.y);
   }
+
+  equals(other: Point): boolean {
+    return this.x == other.x && this.y == other.y;
+  }
 }
 
 export class Size {
@@ -79,17 +83,19 @@ export class Size {
 }
 
 export class Grid<T> {
-  data: T[][];
+  readonly size: Size;
+  #data: T[][];
 
-  constructor({size, cbDefault}: {size: Size, cbDefault: (xy: Point) => T}) {
-    this.data = [];
+  constructor(size: Size, cbDefault: (xy: Point) => T) {
+    this.size = size;
+    this.#data = [];
 
     for (let y = 0; y < size.h; y++) {
       let row = [];
       for (let x = 0; x < size.w; x++) {
         row.push(cbDefault(new Point(x, y)))
       }
-      this.data.push(row);
+      this.#data.push(row);
     }
   }
 
@@ -105,12 +111,12 @@ export class Grid<T> {
       w = w1;
     }
 
-    return new Grid({
-      size: new Size(w, h),
-      cbDefault: (xy) => {
+    return new Grid(
+      new Size(w, h),
+      (xy) => {
         return ary[xy.y].charAt(xy.x);
       }
-    })
+    )
   }
 
   static createGridFromJaggedArray<T>(ary: Array<Array<T>>): Grid<T> {
@@ -125,12 +131,35 @@ export class Grid<T> {
       w = w1;
     }
 
-    return new Grid({
-      size: new Size(w, h),
-      cbDefault: (xy) => {
+    return new Grid(
+      new Size(w, h),
+      (xy) => {
         return ary[xy.y][xy.x];
       }
-    })
+    )
+  }
+
+  map<T2>(cbCell: (content: T, position: Point) => T2) {
+    return new Grid(this.size, (xy) => cbCell(this.get(xy), xy));
+  }
+
+  #checkPosition(position: Point) {
+    if (
+      (position.x < 0 || position.x >= this.size.w || Math.floor(position.x) != position.x) ||
+      (position.y < 0 || position.y >= this.size.h || Math.floor(position.y) != position.y)
+    ) {
+      throw `invalid position for ${this.size}: ${position}`
+    }
+  }
+
+  get(position: Point): T {
+    this.#checkPosition(position);
+    return this.#data[position.y][position.x];
+  }
+
+  set(position: Point, value: T) {
+    this.#checkPosition(position);
+    this.#data[position.y][position.x] = value;
   }
 }