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to Resistor Color in the TypeScript Track

Published at May 16 2021 · 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 TypeScript to install the necessary dependencies:

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

Requirements

Install assignment dependencies:

$ yarn install

Making the test suite pass

Execute the tests with:

$ yarn 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 xit to it.

Source

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.test.ts

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

describe('color code', () => {
  it('Black', () => {
    expect(colorCode('black')).toEqual(0)
  })

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

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

describe('Colors', () => {
  xit('returns all colors', () => {
    expect(COLORS).toEqual([
      'black',
      'brown',
      'red',
      'orange',
      'yellow',
      'green',
      'blue',
      'violet',
      'grey',
      'white',
    ])
  })
})
export const colorCode = (color: string) => {
  return COLORS.indexOf(color)
}

export const COLORS = [
  'black',
  'brown',
  'red',
  'orange',
  'yellow',
  'green',
  'blue',
  'violet',
  'grey',
  'white',
]

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