more type fixes

src/Bundle.ts

@@ -30,8 +30,8 @@ import { basename, isAbsolute } from './utils/path';
 import { timeEnd, timeStart } from './utils/timers';
 
 export default class Bundle {
-	private facadeChunkByModule = new Map<Module, Chunk>();
-	private includedNamespaces = new Set<Module>();
+	private readonly facadeChunkByModule = new Map<Module, Chunk>();
+	private readonly includedNamespaces = new Set<Module>();
 
 	constructor(
 		private readonly outputOptions: NormalizedOutputOptions,
@@ -82,7 +82,7 @@ export default class Bundle {
 	}
 
 	private async addFinalizedChunksToBundle(
-		chunks: Chunk[],
+		chunks: readonly Chunk[],
 		inputBase: string,
 		addons: Addons,
 		outputBundle: OutputBundleWithPlaceholders,
@@ -122,11 +122,11 @@ export default class Bundle {
 	}
 
 	private assignChunkIds(
-		chunks: Chunk[],
+		chunks: readonly Chunk[],
 		inputBase: string,
 		addons: Addons,
 		bundle: OutputBundleWithPlaceholders
-	) {
+	): void {
 		const entryChunks: Chunk[] = [];
 		const otherChunks: Chunk[] = [];
 		for (const chunk of chunks) {
@@ -137,7 +137,7 @@ export default class Bundle {
 		}
 
 		// make sure entry chunk names take precedence with regard to deconflicting
-		const chunksForNaming: Chunk[] = entryChunks.concat(otherChunks);
+		const chunksForNaming = entryChunks.concat(otherChunks);
 		for (const chunk of chunksForNaming) {
 			if (this.outputOptions.file) {
 				chunk.id = basename(this.outputOptions.file);
@@ -241,7 +241,7 @@ export default class Bundle {
 	}
 
 	private prerenderChunks(
-		chunks: Chunk[],
+		chunks: readonly Chunk[],
 		inputBase: string,
 		snippets: GenerateCodeSnippets
 	): void {
@@ -254,7 +254,7 @@ export default class Bundle {
 	}
 }
 
-function getAbsoluteEntryModulePaths(chunks: Chunk[]): string[] {
+function getAbsoluteEntryModulePaths(chunks: readonly Chunk[]): string[] {
 	const absoluteEntryModulePaths: string[] = [];
 	for (const chunk of chunks) {
 		for (const entryModule of chunk.entryModules) {

src/Chunk.ts

@@ -887,7 +887,7 @@ export default class Chunk {
 		return hash.digest('hex').substr(0, 8);
 	}
 
-	private ensureReexportsAreAvailableForModule(module: Module) {
+	private ensureReexportsAreAvailableForModule(module: Module): void {
 		const map = module.getExportNamesByVariable();
 		for (const exportedVariable of map.keys()) {
 			const isSynthetic = exportedVariable instanceof SyntheticNamedExportVariable;
@@ -910,7 +910,10 @@ export default class Chunk {
 		}
 	}
 
-	private finaliseDynamicImports(options: NormalizedOutputOptions, snippets: GenerateCodeSnippets) {
+	private finaliseDynamicImports(
+		options: NormalizedOutputOptions,
+		snippets: GenerateCodeSnippets
+	): void {
 		const stripKnownJsExtensions = options.format === 'amd';
 		for (const [module, code] of this.renderedModuleSources) {
 			for (const { node, resolution } of module.dynamicImports) {
@@ -1218,7 +1221,7 @@ export default class Chunk {
 		return relativePath.startsWith('../') ? relativePath : './' + relativePath;
 	}
 
-	private inlineChunkDependencies(chunk: Chunk) {
+	private inlineChunkDependencies(chunk: Chunk): void {
 		for (const dep of chunk.dependencies) {
 			if (this.dependencies.has(dep)) continue;
 			this.dependencies.add(dep);
@@ -1228,7 +1231,7 @@ export default class Chunk {
 		}
 	}
 
-	private prepareModulesForRendering(snippets: GenerateCodeSnippets) {
+	private prepareModulesForRendering(snippets: GenerateCodeSnippets): void {
 		const accessedGlobalsByScope = this.accessedGlobalsByScope;
 		for (const module of this.orderedModules) {
 			for (const { node, resolution } of module.dynamicImports) {
@@ -1268,7 +1271,7 @@ export default class Chunk {
 		}
 	}
 
-	private setExternalRenderPaths(options: NormalizedOutputOptions, inputBase: string) {
+	private setExternalRenderPaths(options: NormalizedOutputOptions, inputBase: string): void {
 		for (const dependency of [...this.dependencies, ...this.dynamicDependencies]) {
 			if (dependency instanceof ExternalModule) {
 				dependency.setRenderPath(options, inputBase);
@@ -1347,7 +1350,7 @@ export default class Chunk {
 		);
 	}
 
-	private setUpChunkImportsAndExportsForModule(module: Module) {
+	private setUpChunkImportsAndExportsForModule(module: Module): void {
 		const moduleImports = new Set(module.imports);
 		// when we are not preserving modules, we need to make all namespace variables available for
 		// rendering the namespace object

src/ExternalModule.ts

@@ -12,15 +12,15 @@ import { printQuotedStringList } from './utils/printStringList';
 import relativeId from './utils/relativeId';
 
 export default class ExternalModule {
-	declarations: { [name: string]: ExternalVariable } = Object.create(null);
+	readonly declarations: { [name: string]: ExternalVariable } = Object.create(null);
 	defaultVariableName = '';
-	dynamicImporters: string[] = [];
+	readonly dynamicImporters: string[] = [];
 	execIndex = Infinity;
-	exportedVariables = new Map<ExternalVariable, string>();
-	importers: string[] = [];
-	info: ModuleInfo;
+	readonly exportedVariables = new Map<ExternalVariable, string>();
+	readonly importers: string[] = [];
+	readonly info: ModuleInfo;
 	mostCommonSuggestion = 0;
-	nameSuggestions: { [name: string]: number } = Object.create(null);
+	readonly nameSuggestions: { [name: string]: number } = Object.create(null);
 	namespaceVariableName = '';
 	reexported = false;
 	renderPath: string = undefined as never;
@@ -33,7 +33,7 @@ export default class ExternalModule {
 		public readonly id: string,
 		hasModuleSideEffects: boolean | 'no-treeshake',
 		meta: CustomPluginOptions,
-		public renormalizeRenderPath: boolean
+		public readonly renormalizeRenderPath: boolean
 	) {
 		this.suggestedVariableName = makeLegal(id.split(/[\\/]/).pop()!);
 

src/Graph.ts

@@ -23,7 +23,7 @@ import { timeEnd, timeStart } from './utils/timers';
 import { markModuleAndImpureDependenciesAsExecuted } from './utils/traverseStaticDependencies';
 
 function normalizeEntryModules(
-	entryModules: string[] | Record<string, string>
+	entryModules: readonly string[] | Record<string, string>
 ): UnresolvedModule[] {
 	if (Array.isArray(entryModules)) {
 		return entryModules.map(id => ({
@@ -57,7 +57,7 @@ export default class Graph {
 	watchFiles: Record<string, true> = Object.create(null);
 	watchMode = false;
 
-	private externalModules: ExternalModule[] = [];
+	private readonly externalModules: ExternalModule[] = [];
 	private implicitEntryModules: Module[] = [];
 	private modules: Module[] = [];
 	private declare pluginCache?: Record<string, SerializablePluginCache>;
@@ -178,7 +178,7 @@ export default class Graph {
 		}
 	}
 
-	private includeStatements() {
+	private includeStatements(): void {
 		for (const module of [...this.entryModules, ...this.implicitEntryModules]) {
 			markModuleAndImpureDependenciesAsExecuted(module);
 		}
@@ -221,7 +221,7 @@ export default class Graph {
 		}
 	}
 
-	private sortModules() {
+	private sortModules(): void {
 		const { orderedModules, cyclePaths } = analyseModuleExecution(this.entryModules);
 		for (const cyclePath of cyclePaths) {
 			this.options.onwarn({
@@ -238,7 +238,7 @@ export default class Graph {
 		this.warnForMissingExports();
 	}
 
-	private warnForMissingExports() {
+	private warnForMissingExports(): void {
 		for (const module of this.modules) {
 			for (const importDescription of Object.values(module.importDescriptions)) {
 				if (

src/ast/scopes/ChildScope.ts

@@ -51,8 +51,8 @@ export default class ChildScope extends Scope {
 	addUsedOutsideNames(
 		usedNames: Set<string>,
 		format: InternalModuleFormat,
-		exportNamesByVariable: Map<Variable, string[]>,
-		accessedGlobalsByScope: Map<ChildScope, Set<string>>
+		exportNamesByVariable: ReadonlyMap<Variable, string[]>,
+		accessedGlobalsByScope: ReadonlyMap<ChildScope, Set<string>>
 	): void {
 		for (const variable of this.accessedOutsideVariables.values()) {
 			if (variable.included) {
@@ -76,8 +76,8 @@ export default class ChildScope extends Scope {
 
 	deconflict(
 		format: InternalModuleFormat,
-		exportNamesByVariable: Map<Variable, string[]>,
-		accessedGlobalsByScope: Map<ChildScope, Set<string>>
+		exportNamesByVariable: ReadonlyMap<Variable, string[]>,
+		accessedGlobalsByScope: ReadonlyMap<ChildScope, Set<string>>
 	): void {
 		const usedNames = new Set<string>();
 		this.addUsedOutsideNames(usedNames, format, exportNamesByVariable, accessedGlobalsByScope);

src/ast/scopes/ModuleScope.ts

@@ -33,8 +33,8 @@ export default class ModuleScope extends ChildScope {
 
 	deconflict(
 		format: InternalModuleFormat,
-		exportNamesByVariable: Map<Variable, string[]>,
-		accessedGlobalsByScope: Map<ChildScope, Set<string>>
+		exportNamesByVariable: ReadonlyMap<Variable, string[]>,
+		accessedGlobalsByScope: ReadonlyMap<ChildScope, Set<string>>
 	): void {
 		// all module level variables are already deconflicted when deconflicting the chunk
 		for (const scope of this.children)

src/utils/PluginDriver.ts

@@ -86,7 +86,7 @@ export class PluginDriver {
 	constructor(
 		private readonly graph: Graph,
 		private readonly options: NormalizedInputOptions,
-		userPlugins: Plugin[],
+		userPlugins: readonly Plugin[],
 		pluginCache: Record<string, SerializablePluginCache> | undefined,
 		basePluginDriver?: PluginDriver
 	) {
@@ -120,7 +120,7 @@ export class PluginDriver {
 		}
 	}
 
-	public createOutputPluginDriver(plugins: Plugin[]): PluginDriver {
+	public createOutputPluginDriver(plugins: readonly Plugin[]): PluginDriver {
 		return new PluginDriver(this.graph, this.options, plugins, this.pluginCache, this);
 	}
 

src/utils/collapseSourcemaps.ts

@@ -10,8 +10,8 @@ import { error } from './error';
 import { basename, dirname, relative, resolve } from './path';
 
 class Source {
-	content: string;
-	filename: string;
+	readonly content: string;
+	readonly filename: string;
 	isOriginal = true;
 
 	constructor(filename: string, content: string) {
@@ -32,9 +32,9 @@ interface SourceMapSegmentObject {
 }
 
 class Link {
-	mappings: SourceMapSegment[][];
-	names: string[];
-	sources: (Source | Link)[];
+	readonly mappings: SourceMapSegment[][];
+	readonly names: string[];
+	readonly sources: (Source | Link)[];
 
 	constructor(
 		map: { mappings: SourceMapSegment[][]; names: string[] },
@@ -176,7 +176,7 @@ function getCollapsedSourcemap(
 	id: string,
 	originalCode: string,
 	originalSourcemap: ExistingDecodedSourceMap | null,
-	sourcemapChain: DecodedSourceMapOrMissing[],
+	sourcemapChain: readonly DecodedSourceMapOrMissing[],
 	linkMap: (source: Source | Link, map: DecodedSourceMapOrMissing) => Link
 ): Source | Link {
 	let source: Source | Link;
@@ -200,8 +200,8 @@ function getCollapsedSourcemap(
 export function collapseSourcemaps(
 	file: string,
 	map: DecodedSourceMap,
-	modules: Module[],
-	bundleSourcemapChain: DecodedSourceMapOrMissing[],
+	modules: readonly Module[],
+	bundleSourcemapChain: readonly DecodedSourceMapOrMissing[],
 	excludeContent: boolean | undefined,
 	warn: WarningHandler
 ): SourceMap {
@@ -241,7 +241,7 @@ export function collapseSourcemap(
 	id: string,
 	originalCode: string,
 	originalSourcemap: ExistingDecodedSourceMap | null,
-	sourcemapChain: DecodedSourceMapOrMissing[],
+	sourcemapChain: readonly DecodedSourceMapOrMissing[],
 	warn: WarningHandler
 ): ExistingDecodedSourceMap | null {
 	if (!sourcemapChain.length) {

src/utils/commondir.ts

@@ -1,7 +1,7 @@
 import * as path from './path';
 
 // ported from https://github.com/substack/node-commondir
-export default function commondir(files: string[]): string {
+export default function commondir(files: readonly string[]): string {
 	if (files.length === 0) return '/';
 	if (files.length === 1) return path.dirname(files[0]);
 	const commonSegments = files.slice(1).reduce((commonSegments, file) => {

src/utils/deconflictChunk.ts

@@ -41,7 +41,7 @@ const DECONFLICT_IMPORTED_VARIABLES_BY_FORMAT: {
 };
 
 export function deconflictChunk(
-	modules: Module[],
+	modules: readonly Module[],
 	dependenciesToBeDeconflicted: DependenciesToBeDeconflicted,
 	imports: Set<Variable>,
 	usedNames: Set<string>,
@@ -51,9 +51,9 @@ export function deconflictChunk(
 	externalLiveBindings: boolean,
 	chunkByModule: Map<Module, Chunk>,
 	syntheticExports: Set<SyntheticNamedExportVariable>,
-	exportNamesByVariable: Map<Variable, string[]>,
-	accessedGlobalsByScope: Map<ChildScope, Set<string>>,
-	includedNamespaces: Set<Module>
+	exportNamesByVariable: ReadonlyMap<Variable, string[]>,
+	accessedGlobalsByScope: ReadonlyMap<ChildScope, Set<string>>,
+	includedNamespaces: ReadonlySet<Module>
 ): void {
 	const reversedModules = modules.slice().reverse();
 	for (const module of reversedModules) {
@@ -83,7 +83,7 @@ export function deconflictChunk(
 
 function deconflictImportsEsmOrSystem(
 	usedNames: Set<string>,
-	imports: Set<Variable>,
+	imports: ReadonlySet<Variable>,
 	dependenciesToBeDeconflicted: DependenciesToBeDeconflicted,
 	_interop: GetInterop,
 	preserveModules: boolean,
@@ -134,7 +134,7 @@ function deconflictImportsOther(
 	preserveModules: boolean,
 	externalLiveBindings: boolean,
 	chunkByModule: Map<Module, Chunk>
-) {
+): void {
 	for (const chunkOrExternalModule of dependencies) {
 		chunkOrExternalModule.variableName = getSafeName(
 			chunkOrExternalModule.suggestedVariableName,
@@ -206,9 +206,9 @@ function deconflictImportsOther(
 
 function deconflictTopLevelVariables(
 	usedNames: Set<string>,
-	modules: Module[],
-	includedNamespaces: Set<Module>
-) {
+	modules: readonly Module[],
+	includedNamespaces: ReadonlySet<Module>
+): void {
 	for (const module of modules) {
 		for (const variable of module.scope.variables.values()) {
 			if (

src/utils/executionOrder.ts

@@ -13,7 +13,7 @@ export function sortByExecutionOrder(units: OrderedExecutionUnit[]): void {
 	units.sort(compareExecIndex);
 }
 
-export function analyseModuleExecution(entryModules: Module[]): {
+export function analyseModuleExecution(entryModules: readonly Module[]): {
 	cyclePaths: string[][];
 	orderedModules: Module[];
 } {
@@ -72,7 +72,7 @@ function getCyclePath(
 	module: Module,
 	parent: Module,
 	parents: Map<Module | ExternalModule, Module | null>
-) {
+): string[] {
 	const cycleSymbol = Symbol(module.id);
 	const path = [relativeId(module.id)];
 	let nextModule = parent;

src/utils/exportNames.ts

@@ -3,7 +3,7 @@ import RESERVED_NAMES from './RESERVED_NAMES';
 import { toBase64 } from './base64';
 
 export function assignExportsToMangledNames(
-	exports: Set<Variable>,
+	exports: ReadonlySet<Variable>,
 	exportsByName: Record<string, Variable>,
 	exportNamesByVariable: Map<Variable, string[]>
 ): void {
@@ -26,7 +26,7 @@ export function assignExportsToMangledNames(
 }
 
 export function assignExportsToNames(
-	exports: Set<Variable>,
+	exports: ReadonlySet<Variable>,
 	exportsByName: Record<string, Variable>,
 	exportNamesByVariable: Map<Variable, string[]>
 ): void {