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PatrickMcSweeny's solution

to Resistor Color in the JavaScript Track

Published at Aug 28 2019 · 0 comments
Instructions
Test suite
Solution

Resistors have color coded bands, where each color maps to a number. The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.

These 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

Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array: Better Be Right Or Your Great Big Values Go Wrong.

More information on the color encoding of resistors can be found in the Electronic color code Wikipedia article

Setup

Go through the setup instructions for Javascript to install the necessary dependencies:

https://exercism.io/tracks/javascript/installation

Requirements

Install assignment dependencies:

$ npm install

Making the test suite pass

Execute the tests with:

$ 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.

Source

Maud de Vries, Erik Schierboom https://github.com/exercism/problem-specifications/issues/1458

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

resistor-color.spec.js

import { colorCode, COLORS } from './resistor-color'

describe('ResistorColor', () => {
  describe('Color codes', () => {
    test('Black', () => {
      expect(colorCode("black")).toEqual(0)
    })

    xtest('White', () => {
      expect(colorCode("white")).toEqual(9)
    })

    xtest('Orange', () => {
      expect(colorCode("orange")).toEqual(3)
    })
  })

  xtest('Colors', () => {
    expect(COLORS).toEqual(["black","brown","red","orange","yellow","green","blue","violet","grey","white"])
  })
})
export const COLORS = ["black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white"];

export const colorCode = (color) => {
  return COLORS.indexOf(color);
};

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