refactor: infer GradeScale type

src/GradeParser.ts

@@ -1,14 +1,14 @@
-import GradeScale, { GradeScales, GradeScalesTypes, Tuple } from './GradeScale'
+import { GradeScales, GradeScalesTypes, Tuple } from './GradeScale'
 import { scales } from './scales'
 
 /**
  *
  * @param gradeScaleType grade scale type
  * @returns grade scale of provided grade scale name
  */
-export const getScale = (gradeScaleType: GradeScalesTypes): GradeScale | null => {
+export const getScale = <T extends GradeScalesTypes>(gradeScaleType: T): (typeof scales)[T] => {
   const scale = scales[gradeScaleType]
-  if (scale === null) {
+  if (scale == null) {
     console.warn(`Scale: ${gradeScaleType} isn't currently supported`)
   }
   return scale
@@ -53,7 +53,7 @@ export const convertGrade = (
 ): string => {
   const fromScale = getScale(fromGradeScaleType)
   const toScale = getScale(toGradeScaleType)
-  if (fromScale === null || toScale === null) {
+  if (fromScale == null || toScale == null) {
     return ''
   }
   const checkScaleToConvert: boolean = fromScale.allowableConversionType.includes(toGradeScaleType)
@@ -67,6 +67,14 @@ export const convertGrade = (
   return toScale.getGrade(toScore)
 }
 
+export const inferScale = (grade: string): GradeScalesTypes | null => {
+  const matchedScales = Object.values(scales)
+    .map(scale => [scale.name, scale.isType(grade)] as const)
+    .filter(v => v[1])
+  if (matchedScales.length === 1) return matchedScales[0][0]
+  return null
+}
+
 export const isVScale = (grade: string): boolean => {
   const scale = scales[GradeScales.VSCALE]
   if (scale == null) {

src/GradeScale.ts

@@ -2,17 +2,24 @@ import { GradeBandTypes } from './GradeBands'
 
 export type Tuple = [number, number]
 
-export default interface GradeScale {
+export default interface GradeScale<
+  Name extends GradeScalesTypes = GradeScalesTypes,
+  Offset extends number = number,
+> {
   isType: (grade: string) => boolean
   getScore: (grade: string) => number | Tuple
   getGrade: (score: number | Tuple) => string
   getGradeBand: (grade: string) => GradeBandTypes
   displayName: string
-  name: GradeScalesTypes
-  offset: number
+  name: Name
+  offset: Offset
   allowableConversionType: GradeScalesTypes[]
 }
 
+export const infer = <Name extends GradeScalesTypes, Offset extends number>(
+  gradeScale: GradeScale<Name, Offset>
+): GradeScale<Name, Offset> => gradeScale
+
 export const GradeScales = {
   AI: 'ai',
   AID: 'aid',

src/__tests__/GradeParser.ts

@@ -1,4 +1,4 @@
-import { getScoreForSort, convertGrade, getScale } from '../GradeParser'
+import { getScoreForSort, convertGrade, getScale, inferScale } from '../GradeParser'
 import { GradeScales } from '../GradeScale'
 import { VScale, Font, YosemiteDecimal, French, Saxon, AI, WI } from '../scales'
 
@@ -322,4 +322,16 @@ describe('Grade Scales', () => {
       )
     })
   })
+
+  describe('inferScale', () => {
+    test.each([
+      [GradeScales.YDS, '5.10'],
+      [null, '6a'],
+      [null, 'abcdef'],
+      [null, 'abcdef'],
+      [GradeScales.VSCALE, 'V7']
+    ])('detects %s scale for %s', (scale, grade) => {
+      expect(inferScale(grade)).toEqual(scale)
+    })
+  })
 })

src/index.ts

@@ -4,6 +4,7 @@ import {
   getScale,
   getScore,
   getScoreForSort,
+  inferScale,
   isVScale,
   convertGrade
 } from './GradeParser'
@@ -259,7 +260,7 @@ const NORWAY_ARRAY = [
   '12-',
   '12',
   '12+'
-]
+] as const
 
 const CLASS_ARRAY = ['Class 1', 'Class 2', 'Class 3', 'Class 4', 'Class 5']
 
@@ -294,6 +295,7 @@ export {
   getScoreForSort,
   isVScale,
   getScale,
+  inferScale,
   GradeScales,
   GradeScalesTypes,
   GradeBands,

src/scales/ai.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, infer, Tuple } from '../GradeScale'
 import ice_table from '../data/ice.json'
 import { IceGrade } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -9,7 +9,7 @@ const aiGradeRegex = /^(AI)([1-2]|[3-9]\+?|1[0-3]\+?)$/
 
 const isAI = (grade: string): RegExpMatchArray | null => grade.match(aiGradeRegex)
 
-const AIScale: GradeScale = {
+const AIScale = infer({
   displayName: 'AI Grade',
   name: GradeScales.AI,
   offset: 1000,
@@ -42,7 +42,7 @@ const AIScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isAI(grade)

src/scales/aid.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, infer, Tuple } from '../GradeScale'
 import aid_table from '../data/aid.json'
 import { AidGrade } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -8,7 +8,7 @@ import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
 const aidGradeRegex = /^([AC])([0-5]|[2-4]\+)$/i
 const isAid = (grade: string): RegExpMatchArray | null => grade.match(aidGradeRegex)
 
-const AidScale: GradeScale = {
+const AidScale = infer({
   displayName: 'Aid Grade',
   name: GradeScales.AID,
   offset: 1000,
@@ -41,7 +41,7 @@ const AidScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isAid(grade)

src/scales/ewbank.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, getRoundedScoreTuple, Tuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, getRoundedScoreTuple, Tuple, infer } from '../GradeScale'
 import routes from '../data/routes.json'
 import { Route } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -11,7 +11,7 @@ import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
 const ewbankGradeRegex = /^(([1-9])|([1-3][0-9])|(40)){1}(?:(\/)(([1-9])|([1-3][0-9])|(40)))?$/i
 const isEwbank = (grade: string): RegExpMatchArray | null => grade.match(ewbankGradeRegex)
 
-const EwbankScale: GradeScale = {
+const EwbankScale = infer({
   displayName: 'Ewbank Grade',
   name: GradeScales.EWBANK,
   offset: 1000,
@@ -45,7 +45,7 @@ const EwbankScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isEwbank(grade)

src/scales/font.ts

@@ -1,5 +1,5 @@
 import boulder from '../data/boulder.json'
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 
 import { Boulder } from '.'
 import { boulderScoreToBand, GradeBandTypes } from '../GradeBands'
@@ -10,7 +10,7 @@ const fontGradeRegex = /^([1-9][a-c][+]?){1}(?:(\/)([1-9][a-c][+]?))?$/i
 // i.e. 6b+/5a => 6b+/6c
 const isFont = (grade: string): RegExpMatchArray | null => grade.match(fontGradeRegex)
 
-const FontScale: GradeScale = {
+const FontScale = infer({
   displayName: 'Fontainebleau',
   name: GradeScales.FONT,
   offset: 1000,
@@ -43,7 +43,7 @@ const FontScale: GradeScale = {
     const score = getScore(grade)
     return boulderScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isFont(grade)

src/scales/french.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 import routes from '../data/routes.json'
 import { Route } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -9,7 +9,7 @@ const frenchGradeRegex = /^([1-9][a-c][+]?){1}(?:(\/)([1-9][a-c][+]?))?$/i
 // i.e. 6b+/5a => 6b+/6c
 const isFrench = (grade: string): RegExpMatchArray | null => grade.match(frenchGradeRegex)
 
-const FrenchScale: GradeScale = {
+const FrenchScale = infer({
   displayName: 'French Scale',
   name: GradeScales.FRENCH,
   offset: 1000,
@@ -42,7 +42,7 @@ const FrenchScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isFrench(grade)

src/scales/index.ts

@@ -9,7 +9,7 @@ import AI from './ai'
 import Aid from './aid'
 import WI from './wi'
 import UIAA from './uiaa'
-import GradeScale, { GradeScales } from '../GradeScale'
+import { GradeScales } from '../GradeScale'
 export { Aid, VScale, Font, YosemiteDecimal, French, Saxon, UIAA, Ewbank, AI, WI, Norwegian }
 
 export interface Boulder {
@@ -39,10 +39,7 @@ export interface AidGrade {
   aid: string
 }
 
-export const scales: Record<
-  typeof GradeScales[keyof typeof GradeScales],
-GradeScale | null
-> = {
+export const scales = {
   [GradeScales.VSCALE]: VScale,
   [GradeScales.YDS]: YosemiteDecimal,
   [GradeScales.FONT]: Font,
@@ -54,4 +51,4 @@ GradeScale | null
   [GradeScales.AI]: AI,
   [GradeScales.WI]: WI,
   [GradeScales.AID]: Aid
-}
+} as const

src/scales/norwegian.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 import routes from '../data/routes.json'
 import { Route } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -9,7 +9,7 @@ import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
 const norwegianGradeRegex = /^((?:[1-9]|1[0-1])[+-]?)((?:\/)(?:[1-9]|1[0-1])[+-]?)?$/i
 const isNorwegian = (grade: string): RegExpMatchArray | null => grade.match(norwegianGradeRegex)
 
-const Norwegian: GradeScale = {
+const Norwegian = infer({
   displayName: 'Norwegian Scale',
   name: GradeScales.NORWEGIAN,
   offset: 1000,
@@ -42,7 +42,7 @@ const Norwegian: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isNorwegian(grade)

src/scales/saxon.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 import routes from '../data/routes.json'
 import { Route } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -10,7 +10,7 @@ const saxonGradeRegex = /^((([7-9]|1[0-3])([a-c]))|([1-6]))$/i
 // (Roman numerals, e. g. "V", are used - this is not supported)
 const isSaxon = (grade: string): RegExpMatchArray | null => grade.match(saxonGradeRegex)
 
-const SaxonScale: GradeScale = {
+const SaxonScale = infer({
   displayName: 'Saxon Scale',
   name: GradeScales.SAXON,
   offset: 1000,
@@ -43,7 +43,7 @@ const SaxonScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isSaxon(grade)

src/scales/uiaa.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 import routes from '../data/routes.json'
 import { Route } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -10,7 +10,7 @@ const isUIAA = (grade: string): RegExpMatchArray | null => grade.match(uiaaGrade
 // Uses Arabic numerals with +/- signs, e.g. "7", "7-" (easier), or "7+" (harder)
 // (Sometimes roman numerals, e. g. "VII", are used - this is not supported)
 
-const UIAAScale: GradeScale = {
+const UIAAScale = infer({
   displayName: 'UIAA Scale',
   name: GradeScales.UIAA,
   offset: 2000,
@@ -43,7 +43,7 @@ const UIAAScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isUIAA(grade)

src/scales/v.ts

@@ -1,11 +1,11 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, Tuple, getRoundedScoreTuple, infer } from '../GradeScale'
 import boulder from '../data/boulder.json'
 import { Boulder } from '.'
 import { boulderScoreToBand, GradeBandTypes } from '../GradeBands'
 
 const vGradeRegex = /^(V[0-9]{1,2}|VB(?![0-9]))([/+])?([/-])?([0-9]{1,2})?$/i
 
-const VScale: GradeScale = {
+const VScale = infer({
   displayName: 'V Scale',
   name: GradeScales.VSCALE,
   offset: 1000,
@@ -40,7 +40,7 @@ const VScale: GradeScale = {
     const score = getScore(grade)
     return boulderScoreToBand(getAvgScore(score))
   }
-}
+})
 
 export default VScale
 

src/scales/wi.ts

@@ -1,4 +1,4 @@
-import GradeScale, { findScoreRange, getAvgScore, GradeScales, Tuple } from '../GradeScale'
+import { findScoreRange, getAvgScore, GradeScales, infer, Tuple } from '../GradeScale'
 import ice_table from '../data/ice.json'
 import { IceGrade } from '.'
 import { GradeBandTypes, routeScoreToBand } from '../GradeBands'
@@ -9,7 +9,7 @@ const wiGradeRegex = /^(WI)([1-2]|[3-9]\+?|1[0-3]\+?)$/
 
 const isWI = (grade: string): RegExpMatchArray | null => grade.match(wiGradeRegex)
 
-const WIScale: GradeScale = {
+const WIScale = infer({
   displayName: 'WI Grade',
   name: GradeScales.WI,
   offset: 1000,
@@ -42,7 +42,7 @@ const WIScale: GradeScale = {
     const score = getScore(grade)
     return routeScoreToBand(getAvgScore(score))
   }
-}
+})
 
 const getScore = (grade: string): number | Tuple => {
   const parse = isWI(grade)