fix: improve types of generated index.d.ts (#481)

Author: bartveneman

src/collection.test.ts

@@ -0,0 +1,62 @@
+import { test, expect, expectTypeOf } from 'vitest'
+import { Collection, type UniqueWithLocations } from './collection'
+
+let loc = { start: { line: 1, column: 1, offset: 1 }, end: { offset: 2 } }
+
+test('basic collection - size()', () => {
+	let collection = new Collection()
+	collection.p('a', loc)
+	collection.p('a', loc)
+	expect(collection.size()).toEqual(2)
+})
+
+test('count with useLocations=undefined', () => {
+	let collection = new Collection()
+	collection.p('a', loc)
+	collection.p('a', loc)
+
+	let count = collection.c()
+	expect(count).toEqual({
+		total: 2,
+		totalUnique: 1,
+		unique: {
+			a: 2,
+		},
+		uniquenessRatio: 0.5,
+	})
+	expectTypeOf(count['uniqueWithLocations']).toBeUndefined()
+})
+
+test('count with useLocations=false', () => {
+	let collection = new Collection(false)
+	collection.p('a', loc)
+	collection.p('a', loc)
+
+	let count = collection.c()
+	expect(count).toEqual({
+		total: 2,
+		totalUnique: 1,
+		unique: {
+			a: 2,
+		},
+		uniquenessRatio: 0.5,
+	})
+	expectTypeOf(count['uniqueWithLocations']).toBeUndefined()
+})
+
+test('count with useLocations=true', () => {
+	let collection = new Collection(true)
+	collection.p('a', loc)
+	collection.p('a', loc)
+
+	let pos = { offset: 1, length: 1, line: 1, column: 1 }
+	let count = collection.c()
+	expect(count).toEqual({
+		total: 2,
+		totalUnique: 1,
+		unique: {},
+		uniquenessRatio: 0.5,
+		uniqueWithLocations: { a: [pos, pos] },
+	})
+	expectTypeOf(count['uniqueWithLocations']).toMatchObjectType<UniqueWithLocations>()
+})

src/collection.ts

@@ -1,12 +1,26 @@
-import type { CssLocation } from 'css-tree'
+export type Location = {
+	line: number
+	column: number
+	offset: number
+	length: number
+}
+
+export type UniqueWithLocations = Record<string, Location[]>
+
+export type CollectionCount<WithLocations extends boolean = false> = {
+	total: number
+	totalUnique: number
+	unique: Record<string, number>
+	uniquenessRatio: number
+} & (WithLocations extends true ? { uniqueWithLocations: UniqueWithLocations } : { uniqueWithLocations?: undefined })
 
-export class Collection {
+export class Collection<UseLocations extends boolean = false> {
 	#items: Map<string | number, number[]>
 	#total: number
 	#nodes: number[] = []
-	#useLocations: boolean
+	#useLocations: UseLocations
 
-	constructor(useLocations = false) {
+	constructor(useLocations: UseLocations = false as UseLocations) {
 		this.#items = new Map()
 		this.#total = 0
 
@@ -46,8 +60,8 @@ export class Collection {
 		return this.#total
 	}
 
-	c() {
-		let uniqueWithLocations: Map<string | number, { line: number; column: number; offset: number; length: number }[]> = new Map()
+	c(): CollectionCount<UseLocations> {
+		let uniqueWithLocations: Map<string | number, Location[]> = new Map()
 		let unique: Record<string, number> = {}
 		let useLocations = this.#useLocations
 		let items = this.#items
@@ -72,14 +86,23 @@ export class Collection {
 		})
 
 		let total = this.#total
-		let data = {
+
+		if (useLocations) {
+			return {
+				total,
+				totalUnique: size,
+				unique,
+				uniquenessRatio: total === 0 ? 0 : size / total,
+				uniqueWithLocations: Object.fromEntries(uniqueWithLocations),
+			} as unknown as CollectionCount<UseLocations>
+		}
+
+		return {
 			total,
 			totalUnique: size,
 			unique,
 			uniquenessRatio: total === 0 ? 0 : size / total,
-			uniqueWithLocations: useLocations ? Object.fromEntries(uniqueWithLocations) : undefined,
-		}
-
-		return data
+			uniqueWithLocations: undefined,
+		} as unknown as CollectionCount<UseLocations>
 	}
 }

src/context-collection.ts

@@ -1,12 +1,12 @@
 import type { CssLocation } from 'css-tree'
-import { Collection } from './collection.js'
+import { Collection, type CollectionCount } from './collection.js'
 
-export class ContextCollection {
-	#list: Collection
-	#contexts: Map<string, Collection>
-	#useLocations: boolean
+export class ContextCollection<UseLocations extends boolean = false> {
+	#list: Collection<UseLocations>
+	#contexts: Map<string, Collection<UseLocations>>
+	#useLocations: UseLocations
 
-	constructor(useLocations: boolean) {
+	constructor(useLocations: UseLocations) {
 		this.#list = new Collection(useLocations)
 		this.#contexts = new Map()
 		this.#useLocations = useLocations
@@ -29,7 +29,7 @@ export class ContextCollection {
 	}
 
 	count() {
-		let itemsPerContext = new Map()
+		let itemsPerContext: Map<string, CollectionCount<UseLocations>> = new Map()
 
 		for (let [context, value] of this.#contexts.entries()) {
 			itemsPerContext.set(context, value.c())

src/index.ts

@@ -43,18 +43,22 @@ function ratio(part: number, total: number): number {
 	return part / total
 }
 
-let defaults = {
-	useLocations: false,
-}
-
-type Options = {
+export type Options = {
 	/** @description Use Locations (`{ 'item': [{ line, column, offset, length }] }`) instead of a regular count per occurrence (`{ 'item': 3 }`) */
 	useLocations?: boolean
 }
 
-export function analyze(css: string, options: Options = {}) {
-	let settings = Object.assign({}, defaults, options)
-	let useLocations = settings.useLocations === true
+export function analyze(css: string, options?: Options & { useLocations?: false | undefined }): ReturnType<typeof analyzeInternal<false>>
+export function analyze(css: string, options: Options & { useLocations: true }): ReturnType<typeof analyzeInternal<true>>
+export function analyze(css: string, options: Options = {}): any {
+	const useLocations = options.useLocations === true
+	if (useLocations) {
+		return analyzeInternal(css, options, true)
+	}
+	return analyzeInternal(css, options, false)
+}
+
+function analyzeInternal<T extends boolean>(css: string, options: Options, useLocations: T) {
 	let start = Date.now()
 
 	/**
@@ -77,8 +81,14 @@ export function analyze(css: string, options: Options = {}) {
 	let embedSize = 0
 	let embedTypes = {
 		total: 0,
-		/** @type {Map<string, { size: number, count: number } & ({ uniqueWithLocations?: undefined } | ({ uniqueWithLocations: { offset: number, line: number, column: number, length: number }[] })) }>} */
-		unique: new Map(),
+		unique: new Map() as Map<
+			string,
+			{
+				size: number
+				count: number
+				uniqueWithLocations?: { offset: number; line: number; column: number; length: number }[]
+			}
+		>,
 	}
 
 	let startParse = Date.now()
@@ -430,11 +440,11 @@ export function analyze(css: string, options: Options = {}) {
 						}
 
 						if (embedTypes.unique.has(type)) {
-							let item = embedTypes.unique.get(type)
+							let item = embedTypes.unique.get(type)!
 							item.count++
 							item.size += size
 							embedTypes.unique.set(type, item)
-							if (useLocations) {
+							if (useLocations && item.uniqueWithLocations) {
 								item.uniqueWithLocations.push(loc)
 							}
 						} else {

vite.config.js

@@ -6,7 +6,7 @@ import { codecovVitePlugin } from '@codecov/vite-plugin'
 export default defineConfig({
 	build: {
 		lib: {
-			entry: resolve(__dirname, 'src/index.js'),
+			entry: resolve(__dirname, 'src/index.ts'),
 			formats: ['es'],
 		},
 		rollupOptions: {
@@ -16,7 +16,9 @@ export default defineConfig({
 		},
 	},
 	plugins: [
-		dts(),
+		dts({
+			rollupTypes: true,
+		}),
 		codecovVitePlugin({
 			enableBundleAnalysis: process.env.CODECOV_TOKEN !== undefined,
 			bundleName: 'analyzeCss',