feat: progression game

bin/brain-progression.js

@@ -0,0 +1,6 @@
+#!/usr/bin/env node
+
+import brainGames from './brain-games.js';
+import { progressionGame } from '../src/games/index.js';
+
+brainGames.startGame(progressionGame, 'What number is missing in the progression?');

package.json

@@ -8,7 +8,8 @@
     "brain-games": "bin/brain-games.js",
     "brain-even": "bin/brain-even.js",
     "brain-calc": "bin/brain-calc.js",
-    "brain-gcd": "bin/brain-gcd.js"
+    "brain-gcd": "bin/brain-gcd.js",
+    "brain-progression": "bin/brain-progression.js"
   },
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"

src/games/index.js

@@ -1,3 +1,4 @@
 export { default as evenGame } from './evenGame.js';
 export { default as calcGame } from './calcGame.js';
 export { default as gcdGame } from './gcdGame.js';
+export { default as progressionGame } from './progressionGame.js';

src/games/progressionGame.js

@@ -0,0 +1,27 @@
+import { askQuestion, getAnswer, getResponseAfterRound } from '../cli.js';
+
+export default () => {
+  const start = Math.round(Math.random() * 30);
+  const step = Math.round(Math.random() * 20);
+  const length = 10;
+
+  const progression = Array(length).fill(start).map((value, index) => start + index * step);
+  const targetIndex = Math.floor(Math.random() * length);
+  const copyProgression = [...progression];
+
+  copyProgression[targetIndex] = '..';
+
+  const questionText = copyProgression.join(' ');
+
+  askQuestion(questionText);
+
+  const userAnswer = getAnswer('Your answer: ');
+  const rightAnswer = progression[targetIndex];
+
+  const isUserRight = Number(userAnswer) === rightAnswer;
+  const resultString = getResponseAfterRound(isUserRight, userAnswer, rightAnswer);
+
+  console.log(resultString);
+
+  return isUserRight;
+};