Functions 'dragon curve', 'rotate matrix' and tests are done

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["env"]
+}

.travis.yml

@@ -0,0 +1,3 @@
+language: node_js
+node_js:
+  - "lts/*"

package.json

@@ -23,6 +23,10 @@
   },
   "homepage": "https://github.com/front-camp-2018/project-scaffoldings#readme",
   "devDependencies": {
+    "babel-cli": "^6.26.0",
+    "babel-core": "^6.26.3",
+    "babel-jest": "^23.6.0",
+    "babel-preset-env": "^1.7.0",
     "css-loader": "^1.0.0",
     "eslint": "^5.6.1",
     "eslint-plugin-jest": "^21.25.1",

src/dragon-curve/index.js

@@ -1,3 +1,18 @@
 export const dragonCurve = n => {
-  // logic...
+  let initialCode = '1';
+
+  if (n > 0) {
+    for (let i = 1; i < n; i++) {
+      const changedCode = [...initialCode]
+        .reverse()
+        .map(value => value === '1' ? '0' : '1')
+        .join('');
+
+      initialCode = `${initialCode}1${changedCode}`;
+    }
+    return parseInt(initialCode, 10);
+  }
+  throw new Error('Only positive values allowed');
 };
+
+

src/dragon-curve/index.spec.js

@@ -1,5 +1,10 @@
-import {dragonCurve} from './index'
+import {dragonCurve} from './index';
 
 describe('dragonCurve::', () => {
-  // need to implement
+  it('Should return code as "prev code | 1 | reversed prev code with 0 as 1 and 1 as 0"', () => {
+    expect(dragonCurve(1)).toEqual(1);
+    expect(dragonCurve(2)).toEqual(110);
+    expect(dragonCurve(3)).toEqual(1101100);
+    expect(dragonCurve(4)).toEqual(110110011100100);
+  });
 });

src/rotate-matrix/index.js

@@ -1,4 +1,12 @@
 export const rotateMatrix = arr => {
-  // logic...
+  if (checkMatrix(arr)){
+    return arr.map((row, i) => row.map((column, j) => arr[j][i]));
+  }
+  throw new Error('Not a square matrix');
 };
 
+const checkMatrix = arr => {
+  const firstRow = arr[0];
+
+  return arr.every(value => value.length === firstRow.length) && firstRow.length === arr.length;
+};

src/rotate-matrix/index.spec.js

@@ -1,5 +1,36 @@
-import {rotateMatrix} from './index'
+import {rotateMatrix} from './index';
 
 describe('rotateMatrix::', () => {
-  // need to implement
+  it('Should return new matrix, where column = row', () => {
+    expect(rotateMatrix([
+      [1, 2],
+      [3, 4],
+    ])).toEqual([
+      [1, 3],
+      [2, 4],
+    ]);
+    expect(rotateMatrix([
+      [1, 2, 3],
+      [4, 5, 6],
+      [7, 8, 9]
+    ])).toEqual([
+      [1, 4, 7],
+      [2, 5, 8],
+      [3, 6, 9]
+    ]);
+    expect(rotateMatrix([
+      [11, 12, 13, 14, 15],
+      [16, 17, 18, 19, 20],
+      [21, 22, 23, 24, 25],
+      [26, 27, 28, 29, 30],
+      [31, 32, 33, 34, 35]
+    ])).toEqual([
+      [11, 16, 21, 26, 31],
+      [12, 17, 22, 27, 32],
+      [13, 18, 23, 28, 33],
+      [14, 19, 24, 29, 34],
+      [15, 20, 25, 30, 35]
+    ]);
+  });
 });
+