feat: complete resistor-color-trio

Author: yosevu

typescript/resistor-color-trio/resistor-color-trio.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, xit } from '@jest/globals'
+import { describe, it, expect } from '@jest/globals'
 import { decodedResistorValue } from './resistor-color-trio.ts'
 
 describe('Resistor Colors', () => {
@@ -8,47 +8,47 @@ describe('Resistor Colors', () => {
     )
   })
 
-  xit('Blue and grey and brown', () => {
+  it('Blue and grey and brown', () => {
     expect(decodedResistorValue(['blue', 'grey', 'brown'])).toEqual('680 ohms')
   })
 
-  xit('Red and black and red', () => {
+  it('Red and black and red', () => {
     expect(decodedResistorValue(['red', 'black', 'red'])).toEqual('2 kiloohms')
   })
 
-  xit('Green and brown and orange', () => {
+  it('Green and brown and orange', () => {
     expect(decodedResistorValue(['green', 'brown', 'orange'])).toEqual(
       '51 kiloohms'
     )
   })
 
-  xit('Yellow and violet and yellow', () => {
+  it('Yellow and violet and yellow', () => {
     expect(decodedResistorValue(['yellow', 'violet', 'yellow'])).toEqual(
       '470 kiloohms'
     )
   })
 
-  xit('Blue and violet and blue', () => {
+  it('Blue and violet and blue', () => {
     expect(decodedResistorValue(['blue', 'violet', 'blue'])).toEqual(
       '67 megaohms'
     )
   })
 
-  xit('Minimum possible value', () => {
+  it('Minimum possible value', () => {
     expect(decodedResistorValue(['black', 'black', 'black'])).toEqual('0 ohms')
   })
 
-  xit('Maximum possible value', () => {
+  it('Maximum possible value', () => {
     expect(decodedResistorValue(['white', 'white', 'white'])).toEqual(
       '99 gigaohms'
     )
   })
 
-  xit('First two colors make an invalid octal number', () => {
+  it('First two colors make an invalid octal number', () => {
     expect(decodedResistorValue(['black', 'grey', 'black'])).toEqual('8 ohms')
   })
 
-  xit('Ignore extra colors', () => {
+  it('Ignore extra colors', () => {
     expect(decodedResistorValue(['blue', 'green', 'yellow', 'orange'])).toEqual(
       '650 kiloohms'
     )

typescript/resistor-color-trio/resistor-color-trio.ts

@@ -1,3 +1,35 @@
-export function decodedResistorValue() {
-  throw new Error('Remove this statement and implement this function')
+const COLORS = [
+  'black',
+  'brown',
+  'red',
+  'orange',
+  'yellow',
+  'green',
+  'blue',
+  'violet',
+  'grey',
+  'white',
+] as const;
+
+const METRIC_PREFIXES = ['ohms', 'kiloohms', 'megaohms', 'gigaohms'] as const;
+
+type Color = (typeof COLORS)[number];
+
+const colorCode = (color: Color): number => COLORS.indexOf(color);
+
+export function decodedResistorValue(colors: readonly string[]): string {
+  const validColors = colors.slice(0, 3).filter((color): color is Color => COLORS.includes(color as Color));
+  const [tens, ones, zeros] = validColors.map(colorCode);
+
+  const baseValue = tens * 10 + ones;
+  const magnitude = baseValue * Math.pow(10, zeros);
+
+  if (magnitude === 0) {
+    return '0 ohms';
+  }
+
+  const exponent = Math.floor(Math.log10(magnitude) / 3);
+  const adjustedValue = magnitude / Math.pow(10, exponent * 3);
+
+  return `${adjustedValue} ${METRIC_PREFIXES[exponent]}`;
 }