Implement resistor-colors exercise

config.json

@@ -41,6 +41,17 @@
         "strings"
       ]
     },
+    {
+      "slug": "resistor-colors",
+      "uuid": "de800041-3dcc-41b9-b101-7314ff685c93",
+      "core": true,
+      "unlocked_by": null,
+      "difficulty": 2,
+      "topics": [
+        "strings",
+        "arrays"
+      ]
+    },
     {
       "slug": "gigasecond",
       "uuid": "fd7b62d4-266b-4e84-a526-bf3d47901216",
@@ -1317,7 +1328,6 @@
         "math"
       ]
     },
-
     {
       "slug": "trinary",
       "uuid": "1acf1d2d-a25e-4576-94de-0470abc872d9",

exercises/resistor-colors/.eslintrc

@@ -0,0 +1,26 @@
+{
+  "root": true,
+  "parser": "babel-eslint",
+  "parserOptions": {
+    "ecmaVersion": 7,
+    "sourceType": "module"
+  },
+  "env": {
+    "es6": true,
+    "node": true,
+    "jest": true
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:import/errors",
+    "plugin:import/warnings"
+  ],
+  "rules": {
+    "linebreak-style": "off",
+
+    "import/extensions": "off",
+    "import/no-default-export": "off",
+    "import/no-unresolved": "off",
+    "import/prefer-default-export": "off"
+  }
+}

exercises/resistor-colors/README.md

@@ -0,0 +1,54 @@
+# Resistor Colors
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_. For this exercise, you need to know two things about them:
+
+* Each resistor has a resistance value.
+* Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
+To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values. Each band acts as a digit of a number. For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.
+
+In this exercise, you are going to create a helpful program so that you don't have to remember the values of the bands. The program will take two colors as input, and output the correct number.
+
+The band colors are encoded as follows:
+
+- Black: 0
+- Brown: 1
+- Red: 2
+- Orange: 3
+- Yellow: 4
+- Green: 5
+- Blue: 6
+- Violet: 7
+- Grey: 8
+- White: 9
+
+## Setup
+
+Go through the setup instructions for Javascript to
+install the necessary dependencies:
+
+[https://exercism.io/tracks/javascript/installation](https://exercism.io/tracks/javascript/installation)
+
+## Requirements
+
+Install assignment dependencies:
+
+```bash
+$ npm install
+```
+
+## Making the test suite pass
+
+Execute the tests with:
+
+```bash
+$ npm test
+```
+
+In the test suites all tests but the first have been skipped.
+
+Once you get a test passing, you can enable the next one by
+changing `xtest` to `test`.
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/resistor-colors/babel.config.js

@@ -0,0 +1,14 @@
+module.exports = {
+  presets: [
+    [
+      '@babel/env',
+      {
+        targets: {
+          node: 'current',
+        },
+        useBuiltIns: false,
+      },
+
+    ],
+  ],
+};

exercises/resistor-colors/example.js

@@ -0,0 +1,8 @@
+const COLORS = [
+  'black', 'brown', 'red', 'orange', 'yellow', 'green',
+  'blue', 'violet', 'grey', 'white',
+];
+
+const reducer = (acc, color, i) => acc + COLORS.indexOf(color) * (10 ** i);
+
+export const value = colors => colors.reverse().reduce(reducer, 0);

exercises/resistor-colors/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "exercism-javascript",
+  "version": "0.0.0",
+  "description": "Exercism exercises in Javascript.",
+  "author": "Katrina Owen",
+  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/javascript"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.2.3",
+    "@babel/core": "^7.4.0",
+    "@babel/preset-env": "^7.4.2",
+    "babel-eslint": "^10.0.1",
+    "babel-jest": "^24.5.0",
+    "eslint": "^5.15.3",
+    "eslint-plugin-import": "^2.16.0",
+    "jest": "^24.5.0"
+  },
+  "jest": {
+    "modulePathIgnorePatterns": [
+      "package.json"
+    ]
+  },
+  "scripts": {
+    "test": "jest --no-cache ./*",
+    "watch": "jest --no-cache --watch ./*",
+    "lint": "eslint .",
+    "lint-test": "eslint . && jest --no-cache ./* "
+  },
+  "license": "MIT",
+  "dependencies": {}
+}

exercises/resistor-colors/resistor-colors.spec.js

@@ -0,0 +1,19 @@
+import { value } from './resistor-colors.js';
+
+describe('Resistor Colors', () => {
+  test('Brown and black', () => {
+    expect(value(['brown', 'black'])).toEqual(10);
+  });
+
+  xtest('Blue and grey', () => {
+    expect(value(['blue', 'grey'])).toEqual(68);
+  });
+
+  xtest('Yellow and violet', () => {
+    expect(value(['yellow', 'violet'])).toEqual(47);
+  });
+
+  xtest('Orange and orange', () => {
+    expect(value(['orange', 'orange'])).toEqual(33);
+  });
+});