add progression game

Author: daria-z

Makefile

@@ -10,6 +10,9 @@ brain-even:
 brain-calculator:
 	node bin/brain-calculator.js
 
+brain-progression:
+	node bin/brain-progression.js
+
 publish:
 	npm publish --dry-run
 

bin/brain-progression.js

@@ -0,0 +1,4 @@
+#!/usr/bin/env node
+import { progression } from '../src/cli.js';
+
+progression();

src/cli.js

@@ -2,5 +2,6 @@ import userGreeting from './games/userGreeting.js';
 import evenChecking from './games/evenChecking.js';
 import calculator from './games/brain-calculator.js';
 import gcd from './games/gcd.js';
+import progression from './games/brain-progression.js';
 
-export { userGreeting, evenChecking, calculator, gcd };
+export { userGreeting, evenChecking, calculator, gcd, progression };

src/games/brain-progression.js

@@ -0,0 +1,7 @@
+import gamesWrapper from "./utils/gamesWrapper.js";
+import { rule, logic } from "./gamesLogic/progression.js";
+
+export default () => {
+  gamesWrapper(rule, logic);
+};
+

src/games/calculator.js

@@ -0,0 +1,20 @@
+import generateRandomNumber from "../utils/generateRandomNumber.js";
+
+export const rule = 'What number is missing in the progression?';
+
+export const logic = () => {
+  const missedPosition = generateRandomNumber(1, 10);
+  const progressionFirstNumber = generateRandomNumber(1, 30);
+  const progressionDiff = generateRandomNumber(1, 5);
+  const progression = [progressionFirstNumber];
+
+  for (let i = 0; i < 10; i += 1) {
+    const nextNumber = progression[progression.length - 1] + progressionDiff;
+    progression.push(nextNumber);
+  };
+  const correctAnswer = progression[missedPosition];
+  progression[missedPosition] = '...';
+
+  return [progression.join(' '), correctAnswer];
+}
+