Move live or die logic to Cell class

remarcmij · stasel · commit 32ee8fd0da10 · 2025-03-04T15:35:19.000+01:00
diff --git a/Week4/prep-exercises/2-game-of-life/Cell.js b/Week4/prep-exercises/2-game-of-life/Cell.js
@@ -37,4 +37,21 @@ export default class Cell {
       );
     }
   }
+
+  liveAndLetDie(aliveNeighbors) {
+    if (aliveNeighbors === 2) {
+      // Living cell remains living, dead cell remains dead
+      this.nextAlive = this.alive;
+    } else if (aliveNeighbors === 3) {
+      // Dead cell becomes living, living cell remains living
+      this.nextAlive = true;
+    } else {
+      // Living cell dies, dead cell remains dead
+      this.nextAlive = false;
+    }
+  }
+
+  update() {
+    this.alive = this.nextAlive;
+  }
 }
diff --git a/Week4/prep-exercises/2-game-of-life/Grid.js b/Week4/prep-exercises/2-game-of-life/Grid.js
@@ -52,23 +52,11 @@ export default class Grid {
 
   update() {
     this.forEachCell((cell) => {
-      const numAlive = this.countLivingNeighbors(cell);
-
-      if (numAlive === 2) {
-        // Living cell remains living, dead cell remains dead
-        cell.nextAlive = cell.alive;
-      } else if (numAlive === 3) {
-        // Dead cell becomes living, living cell remains living
-        cell.nextAlive = true;
-      } else {
-        // Living cell dies, dead cell remains dead
-        cell.nextAlive = false;
-      }
+      const aliveNeighbors = this.countLivingNeighbors(cell);
+      cell.liveAndLetDie(aliveNeighbors);
     });
 
-    this.forEachCell((cell) => {
-      cell.alive = cell.nextAlive;
-    });
+    this.forEachCell((cell) => cell.update());
   }
 
   render(context) {
diff --git a/Week4/prep-exercises/2-game-of-life/README.md b/Week4/prep-exercises/2-game-of-life/README.md
@@ -29,6 +29,8 @@ This class represents a single cell.
 |----------|-------------|
 | constructor() | Initializes the cell's `x` and `y` coordinates from arguments passed to the constructor. It randomly sets the initial `alive` boolean state of the cell and initializes its next `alive` state. |
 | draw() | Draws the cell on the canvas. The visual representation depends on whether the cell is alive or dead. |
+| liveAndLetDie() | Determines the next state (alive or dead) depending on the number of living neighbors of the cell, by applying the rules of the Game Of Life. |
+| update() | Updates the state of the cell (alive or dead) as set previously by `liveAndLetDie()`.
 
 ### `class Grid`
 
@@ -41,7 +43,7 @@ This class manages the game grid, made up of cells.
 | `forEachCell()` | Executes a callback function for each cell in the two-dimensional grid array, passing the cell as a parameter to the callback. |
 | `isAlive()` | Determines whether a cell at the given coordinates is alive or dead. The coordinates could potentially be off-grid. Off-grid cells are presumed to be dead. The function returns one if the given cell is alive or zero if its dead. |
 | `countLivingNeighbors()` | Counts the number of living neighbors for a given cell. Each cell has eight neighbors, some of which may be off-grid if the cell is located at an edge or a corner of the grid. |
-| `update()` | Iterates through all cells of the grid and computes the new state of each cell by applying the rules of the Game Of Life. |
+| `update()` | Iterates through all cells of the grid and computes the new state of each cell. |
 | `render()` | Iterates through all cells of the grid and draws each cell onto the canvas. |
 
 ### `class Game`
@@ -83,7 +85,7 @@ In the supplied JavaScript code the color of all living cells is a single shade
    |    3     |  0.75   |
    |    4+    |    1    |
 
-3. In the `update` method of the `Grid` class add code to update the `lifeTime` value of each cell:
+3. In the `liveAndLetDie()` method of the `Cell` class add code to update the `lifeTime` value of each cell:
 
    - A living cell that remains living should have its `lifeTime` incremented by one.
    - A living cell that dies should have its `lifeTime` reset to zero.
