Refactor QuickScoreConfig to extend BaseConfig

Add useSkipReduction() method and emptyQueryScore to the config.
Move constants into config object so they can be overridden.
Use emptyQueryScore = 0 with the default config.
Rename config() to createConfig().
Create a config from the configOptions in createScorer().
Fix zero score tests.
Remove babel key from package.json.
Add babel-plugin-external-helpers to avoid duplicate class call checks.
Update eslintrc.

.eslintrc.js

@@ -29,7 +29,7 @@ module.exports = {
 			"off",
 			"never"
 		],
-		"class-methods-use-this": "error",
+		"class-methods-use-this": "off",
 		"comma-dangle": "error",
 		"comma-spacing": [
 			"error",
@@ -88,7 +88,7 @@ module.exports = {
 			"error",
 			"always"
 		],
-		"max-classes-per-file": "error",
+		"max-classes-per-file": "off",
 		"max-depth": "off",
 		"max-len": "off",
 		"max-lines": "error",
@@ -244,7 +244,7 @@ module.exports = {
 		"prefer-const": "error",
 		"prefer-destructuring": "error",
 		"prefer-numeric-literals": "error",
-		"prefer-object-spread": "error",
+		"prefer-object-spread": "off",
 		"prefer-promise-reject-errors": "error",
 		"prefer-reflect": "error",
 		"prefer-rest-params": "error",

package.json

@@ -23,15 +23,6 @@
     "test:coverage": "jest --coverage --runInBand --env node",
     "debug": "node debug/debug-quick-score.js"
   },
-  "babel": {
-    "env": {
-      "test": {
-        "presets": [
-          "env"
-        ]
-      }
-    }
-  },
   "jest": {
     "collectCoverageFrom": [
       "src/*.js",
@@ -45,6 +36,7 @@
   "devDependencies": {
     "ajv": "^6.5.2",
     "babel": "^6.23.0",
+    "babel-plugin-external-helpers": "^6.22.0",
     "babel-preset-env": "^1.7.0",
     "eslint": "^5.3.0",
     "jest": "^23.3.0",

rollup.config.js

@@ -17,9 +17,10 @@ const BabelConfig = {
 	exclude: "**/node_modules/**",
 		// tell babel to not transform modules, so that rollup can do it
 	presets: [
-		["env", {
-			modules: false
-		}]
+		["env", { modules: false }]
+	],
+	plugins: [
+		"external-helpers"
 	]
 };
 

src/config.js

@@ -1,28 +1,43 @@
-const WordSeparators = "-/\\:()<>%._=&[]+ \t\n\r";
-const UppercaseLetters = (function() {
-	const charCodeA = "A".charCodeAt(0);
-	const uppercase = [];
+const BaseConfigDefaults = {
+	wordSeparators: "-/\\:()<>%._=&[]+ \t\n\r",
+	uppercaseLetters: (function() {
+		const charCodeA = "A".charCodeAt(0);
+		const uppercase = [];
 
-	for (let i = 0; i < 26; i++) {
-		uppercase.push(String.fromCharCode(charCodeA + i));
+		for (let i = 0; i < 26; i++) {
+			uppercase.push(String.fromCharCode(charCodeA + i));
+		}
+
+		return uppercase.join("");
+	})(),
+	ignoredScore: 0.9,
+	skippedScore: 0.15,
+	emptyQueryScore: 0
+};
+const QSConfigDefaults = {
+	longStringLength: 151,
+	maxMatchStartPct: 0.15,
+	minMatchDensityPct: 0.75,
+	maxMatchDensityPct: 0.95,
+	beginningOfStringPct: 0.1
+};
+
+
+class BaseConfig {
+	constructor(
+		options)
+	{
+		Object.assign(this, BaseConfigDefaults, options);
 	}
 
-	return uppercase.join("");
-})();
-const IgnoredScore = 0.9;
-const SkippedScore = 0.15;
-const LongStringLength = 151;
-//const MaxMatchStartPct = .15;
-const MinMatchDensityPct = .75;
-const MaxMatchDensityPct = .95;
-const BeginningOfStringPct = .1;
-const ConfigDefaults = {
-	wordSeparators: WordSeparators,
-	uppercaseLetters: UppercaseLetters,
-	ignoredScore: IgnoredScore,
-	skippedScore: SkippedScore,
-	skipReduction: true,
-	adjustRemainingScore: function(
+
+	useSkipReduction()
+	{
+		return true;
+	}
+
+
+	adjustRemainingScore(
 		string,
 		query,
 		remainingScore,
@@ -32,7 +47,48 @@ const ConfigDefaults = {
 		matchedRange,
 		fullMatchedRange)
 	{
-		const isShortString = string.length < LongStringLength;
+			// use the original Quicksilver expression for the remainingScore
+		return remainingScore * remainingSearchRange.length;
+	}
+}
+
+
+class QuickScoreConfig extends BaseConfig {
+	constructor(
+		options)
+	{
+		super(Object.assign({}, QSConfigDefaults, options));
+	}
+
+
+	useSkipReduction(
+		string,
+		query,
+		remainingScore,
+		searchRange,
+		remainingSearchRange,
+		matchedRange,
+		fullMatchedRange)
+	{
+		const len = string.length;
+		const isShortString = len < this.longStringLength;
+		const matchStartPercentage = fullMatchedRange.location / len;
+
+		return isShortString || matchStartPercentage < this.maxMatchStartPct;
+	}
+
+
+	adjustRemainingScore(
+		string,
+		query,
+		remainingScore,
+		skippedSpecialChar,
+		searchRange,
+		remainingSearchRange,
+		matchedRange,
+		fullMatchedRange)
+	{
+		const isShortString = string.length < this.longStringLength;
 		const matchStartPercentage = fullMatchedRange.location / string.length;
 		let matchRangeDiscount = 1;
 		let matchStartDiscount = (1 - matchStartPercentage);
@@ -45,38 +101,30 @@ const ConfigDefaults = {
 		if (!skippedSpecialChar) {
 			matchRangeDiscount = query.length / fullMatchedRange.length;
 			matchRangeDiscount = (isShortString &&
-				matchStartPercentage <= BeginningOfStringPct &&
-				matchRangeDiscount >= MinMatchDensityPct) ?
+				matchStartPercentage <= this.beginningOfStringPct &&
+				matchRangeDiscount >= this.minMatchDensityPct) ?
 				1 : matchRangeDiscount;
-			matchStartDiscount = matchRangeDiscount >= MaxMatchDensityPct ?
+			matchStartDiscount = matchRangeDiscount >= this.maxMatchDensityPct ?
 				1 : matchStartDiscount;
 		}
 
 			// discount the scores of very long strings
-		return remainingScore * Math.min(remainingSearchRange.length, LongStringLength) *
+		return remainingScore * Math.min(remainingSearchRange.length, this.longStringLength) *
 			matchRangeDiscount * matchStartDiscount;
 	}
-};
-
-
-class QuickScoreConfig {
-	constructor(
-		options)
-	{
-		Object.assign(this, ConfigDefaults, options);
-	}
 }
 
 
-export function config(
+export function createConfig(
 	options)
 {
 	return new QuickScoreConfig(options);
 }
 
 
-export const DefaultConfig = config();
-export const QuicksilverConfig = config({
+export const DefaultConfig = createConfig();
+export const QuicksilverConfig = new BaseConfig({
+	emptyQueryScore: 0.9,
 	adjustRemainingScore: function(
 		string,
 		query,

src/quick-score.js

@@ -2,10 +2,6 @@ import {Range} from "./range";
 import {DefaultConfig} from "./config";
 
 
-const LongStringLength = 151;
-const MaxMatchStartPct = .15;
-
-
 export function quickScore(
 	string,
 	query,
@@ -14,7 +10,7 @@ export function quickScore(
 	stringRange = new Range(0, string.length))
 {
 	if (!query) {
-		return config.ignoredScore;
+		return config.emptyQueryScore;
 	}
 
 	const lcString = string.toLocaleLowerCase();
@@ -66,16 +62,15 @@ export function quickScore(
 			const remainingScore = calcScore(remainingSearchRange, remainingQueryRange, fullMatchedRange);
 
 			if (remainingScore) {
-				const isShortString = string.length < LongStringLength;
-				const matchStartPercentage = fullMatchedRange.location / string.length;
-				const useSkipReduction = config.skipReduction === true &&
-					(isShortString || matchStartPercentage < MaxMatchStartPct);
 				let score = remainingSearchRange.location - searchRange.location;
 					// default to true since we only want to apply a discount if
 					// we hit the final else clause below, and we won't get to
 					// any of them if the match is right at the start of the
 					// searchRange
 				let skippedSpecialChar = true;
+				const useSkipReduction = config.useSkipReduction(string, query,
+					remainingScore, remainingSearchRange, searchRange,
+					remainingSearchRange, matchedRange, fullMatchedRange);
 
 				if (matchedRange.location > searchRange.location) {
 						// some letters were skipped when finding this match, so