Add util function getTimeStr and being testing

js/__tests__/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "env": {
+    "jest": true
+  }
+}

js/__tests__/utils-test.js

@@ -0,0 +1,34 @@
+jest.unmock('../utils');
+
+import {getTimeObj, getTimeStr} from '../utils';
+
+describe('getTimeObj', () => {
+  it('expresses seconds as an object', () => {
+    const actual = getTimeObj(1234);
+    const expected = {
+      minutesFirstDigit: 2,
+      minutesSecondDigit: 0,
+      secondsFirstDigit: 3,
+      secondsSecondDigit: 4
+    };
+    expect(actual).toEqual(expected);
+  });
+});
+
+describe('getTimeStr', () => {
+  it('expresses seconds as string', () => {
+    const actual = getTimeStr(1234);
+    const expected = '20:34';
+    expect(actual).toEqual(expected);
+  });
+  it('pads with zeros', () => {
+    const actual = getTimeStr(5);
+    const expected = '00:05';
+    expect(actual).toEqual(expected);
+  });
+  it('truncates extra minutes', () => {
+    const actual = getTimeStr(540000);
+    const expected = '9000:00';
+    expect(actual).toEqual(expected);
+  });
+});

js/utils.js

@@ -10,7 +10,19 @@ const getTimeObj = (time) => {
   };
 };
 
-module.exports = {
-  getTimeObj
+const getTimeStr = (time) => {
+  const timeObj = getTimeObj(time);
+  return [
+    timeObj.minutesFirstDigit,
+    timeObj.minutesSecondDigit,
+    ':',
+    timeObj.secondsFirstDigit,
+    timeObj.secondsSecondDigit
+  ].join('');
+};
+
+module.exports = {
+  getTimeObj,
+  getTimeStr
 };
 

package.json

@@ -7,7 +7,8 @@
     "lint": "eslint js/*.js js/*.jsx",
     "build": "webpack --optimize-minimize",
     "serve": "webpack-dev-server",
-    "weight": "npm run build && gzip-size built/winamp.js | pretty-bytes"
+    "weight": "npm run build && gzip-size built/winamp.js | pretty-bytes",
+    "test": "jest"
   },
   "repository": {
     "type": "git",
@@ -28,7 +29,9 @@
   "devDependencies": {
     "babel-cli": "^6.10.1",
     "babel-core": "^6.10.4",
+    "babel-jest": "^13.2.2",
     "babel-loader": "^6.2.4",
+    "babel-polyfill": "^6.9.1",
     "babel-preset-es2015": "^6.9.0",
     "babel-preset-react": "^6.11.1",
     "css-loader": "^0.23.1",
@@ -36,6 +39,7 @@
     "eslint-plugin-react": "^5.2.2",
     "file-loader": "^0.9.0",
     "gzip-size-cli": "^1.0.0",
+    "jest-cli": "^13.2.3",
     "pretty-bytes-cli": "^1.0.0",
     "style-loader": "^0.13.1",
     "url-loader": "^0.5.7",