Add source maps; add trap location generator

karma.conf.js

@@ -21,6 +21,7 @@ module.exports = function(config) {
 
     webpack: {
       module: webpackConfig.module,
+      plugins: webpackConfig.plugins,
       resolve: webpackConfig.resolve
     },
 

package.json

@@ -28,6 +28,7 @@
     "karma-mocha": "^1.3.0",
     "karma-webpack": "^3.0.5",
     "mocha": "^5.2.0",
+    "source-map-loader": "^0.2.4",
     "webpack": "^4.22.0",
     "webpack-cli": "^3.1.2",
     "webpack-dev-server": "^3.1.10"

src/services/trap-location-generator.js

@@ -0,0 +1,25 @@
+class LocationGenerator {
+  getRandomInt(max) {
+    return Math.floor(Math.random() * Math.floor(max));
+  }
+
+  generateLocations(width, height, trapCount) {
+    const traps = {};
+
+    for (let n = 0; n < trapCount; n++) {
+      const x = this.getRandomInt(width);
+      const y = this.getRandomInt(height);
+
+      if (traps[x]) {
+        traps[x].push(y);
+      }
+      else {
+        traps[x] = [y];
+      }
+    }
+
+    return traps;
+  }
+}
+
+export default LocationGenerator;

test/services/trap-location-generator.spec.js

@@ -0,0 +1,52 @@
+/* global describe, it */
+
+import { expect } from 'chai';
+import Generator from '../../src/services/trap-location-generator';
+
+describe('trap location generator', function() {
+  it('returns new trap locations', function() {
+
+    // Arrange
+
+    const count = 3;
+    const height = 3;
+    const width = 3;
+
+    // Act
+
+    const generator = new Generator();
+    const locations = generator.generateLocations(width, height, count);
+
+    // Assert
+
+    const keys = Object.keys(locations);
+    expect(keys.length).to.be.greaterThan(0);
+
+    keys.forEach(xValue => {
+      expect(Number(xValue), 'x co-ordinate should be at least 0').to.be.at.least(0);
+
+      locations[xValue].forEach(yValue => {
+        expect(yValue, 'y co-ordinate should be at least 0').to.be.at.least(0);
+      });
+    });
+  });
+
+  it('returns different locations each time', function() {
+
+    // Arrange
+
+    const count = 3;
+    const height = 3;
+    const width = 3;
+
+    // Act
+
+    const generator = new Generator();
+    const locations1 = generator.generateLocations(width, height, count);
+    const locations2 = generator.generateLocations(width, height, count);
+
+    // Assert
+
+    expect(locations1).not.to.deep.equal(locations2);
+  });
+});

webpack.config.js

@@ -1,4 +1,6 @@
-/* global module, __dirname */
+/* global __dirname, module, require */
+
+const webpack = require('webpack');
 
 module.exports = {
   devServer: {
@@ -7,6 +9,13 @@ module.exports = {
   },
 
   mode: 'development',
+
+  plugins: [
+    new webpack.SourceMapDevToolPlugin({
+      filename: null, // inline sourcemap
+      test: /\.js($|\?)/i // case-insensitive match for js files
+    })
+  ],
 
   entry: './src/index.jsx',