refactor: some code and type fixes

cli/run/batchWarnings.ts

@@ -14,7 +14,7 @@ export interface BatchWarnings {
 
 export default function batchWarnings(): BatchWarnings {
 	let count = 0;
-	let deferredWarnings = new Map<keyof typeof deferredHandlers, RollupWarning[]>();
+	const deferredWarnings = new Map<keyof typeof deferredHandlers, RollupWarning[]>();
 	let warningOccurred = false;
 
 	return {
@@ -59,7 +59,7 @@ export default function batchWarnings(): BatchWarnings {
 				deferredHandlers[code](deferredWarnings.get(code)!);
 			}
 
-			deferredWarnings = new Map();
+			deferredWarnings.clear();
 			count = 0;
 		},
 
@@ -224,13 +224,12 @@ const deferredHandlers: {
 		title('Unresolved dependencies');
 		info('https://rollupjs.org/guide/en/#warning-treating-module-as-external-dependency');
 
-		const dependencies = new Map();
+		const dependencies = new Map<string, string[]>();
 		for (const warning of warnings) {
-			getOrCreate(dependencies, warning.source, () => []).push(warning.importer);
+			getOrCreate(dependencies, warning.source, () => []).push(warning.importer!);
 		}
 
-		for (const dependency of dependencies.keys()) {
-			const importers = dependencies.get(dependency);
+		for (const [dependency, importers] of dependencies) {
 			stderr(`${bold(dependency)} (imported by ${importers.join(', ')})`);
 		}
 	},
@@ -243,7 +242,7 @@ const deferredHandlers: {
 					' imported from external module "' +
 					warning.source +
 					'" but never used in ' +
-					printQuotedStringList((warning.sources as string[]).map(id => relativeId(id)))
+					printQuotedStringList(warning.sources!.map(id => relativeId(id)))
 			);
 		}
 	}

cli/run/index.ts

@@ -1,3 +1,4 @@
+import { env } from 'process';
 import type { MergedRollupOptions } from '../../src/rollup/types';
 import { isWatchEnabled } from '../../src/utils/options/mergeOptions';
 import { getAliasName } from '../../src/utils/relativeId';
@@ -48,11 +49,7 @@ export default async function runRollup(command: Record<string, any>): Promise<v
 		environment.forEach((arg: string) => {
 			arg.split(',').forEach((pair: string) => {
 				const [key, ...value] = pair.split(':');
-				if (value.length) {
-					process.env[key] = value.join(':');
-				} else {
-					process.env[key] = String(true);
-				}
+				env[key] = value.length === 0 ? String(true) : value.join(':');
 			});
 		});
 	}

cli/run/timings.ts

@@ -3,10 +3,9 @@ import type { SerializedTimings } from '../../src/rollup/types';
 import { bold, underline } from '../../src/utils/colors';
 
 export function printTimings(timings: SerializedTimings): void {
-	Object.keys(timings).forEach(label => {
+	Object.entries(timings).forEach(([label, [time, memory, total]]) => {
 		const appliedColor =
 			label[0] === '#' ? (label[1] !== '#' ? underline : bold) : (text: string) => text;
-		const [time, memory, total] = timings[label];
 		const row = `${label}: ${time.toFixed(0)}ms, ${prettyBytes(memory)} / ${prettyBytes(total)}`;
 		console.info(appliedColor(row));
 	});

src/Bundle.ts

@@ -35,7 +35,7 @@ export default class Bundle {
 
 	constructor(
 		private readonly outputOptions: NormalizedOutputOptions,
-		private readonly unsetOptions: Set<string>,
+		private readonly unsetOptions: ReadonlySet<string>,
 		private readonly inputOptions: NormalizedInputOptions,
 		private readonly pluginDriver: PluginDriver,
 		private readonly graph: Graph
@@ -189,14 +189,14 @@ export default class Bundle {
 				);
 				(file as OutputAsset).type = 'asset';
 			}
-			if (this.outputOptions.validate && typeof (file as OutputChunk).code == 'string') {
+			if (this.outputOptions.validate && 'code' in file) {
 				try {
-					this.graph.contextParse((file as OutputChunk).code, {
+					this.graph.contextParse(file.code, {
 						allowHashBang: true,
 						ecmaVersion: 'latest'
 					});
 				} catch (err: any) {
-					this.inputOptions.onwarn(errChunkInvalid(file as OutputChunk, err));
+					this.inputOptions.onwarn(errChunkInvalid(file, err));
 				}
 			}
 		}

src/Chunk.ts

@@ -319,7 +319,7 @@ export default class Chunk {
 		const facades: Chunk[] = [];
 		const entryModules = new Set([...this.entryModules, ...this.implicitEntryModules]);
 		const exposedVariables = new Set<Variable>(
-			this.dynamicEntryModules.map(module => module.namespace)
+			this.dynamicEntryModules.map(({ namespace }) => namespace)
 		);
 		for (const module of entryModules) {
 			if (module.preserveSignature) {
@@ -331,11 +331,10 @@ export default class Chunk {
 		for (const module of entryModules) {
 			const requiredFacades: FacadeName[] = Array.from(
 				new Set(
-					module.chunkNames.filter(({ isUserDefined }) => isUserDefined).map(({ name }) => name)
-				),
-				name => ({
-					name
-				})
+					module.chunkNames
+						.filter(({ isUserDefined }) => isUserDefined)
+						.map(({ name }) => ({ name }))
+				)
 			);
 			if (requiredFacades.length === 0 && module.isUserDefinedEntryPoint) {
 				requiredFacades.push({});
@@ -451,7 +450,7 @@ export default class Chunk {
 			const extension = extname(sanitizedId);
 			const fileName = renderNamePattern(pattern, 'output.entryFileNames', {
 				assetExtname: () => (NON_ASSET_EXTENSIONS.includes(extension) ? '' : extension),
-				ext: () => extension.substr(1),
+				ext: () => extension.substring(1),
 				extname: () => extension,
 				format: () => options.format as string,
 				name: () => this.getChunkName()
@@ -467,7 +466,7 @@ export default class Chunk {
 			const extension = extname(sanitizedId);
 			const fileName = renderNamePattern(pattern, 'output.entryFileNames', {
 				assetExtname: () => (NON_ASSET_EXTENSIONS.includes(extension) ? '' : extension),
-				ext: () => extension.substr(1),
+				ext: () => extension.substring(1),
 				extname: () => extension,
 				format: () => options.format as string,
 				name: () => getAliasName(sanitizedId)
@@ -1162,7 +1161,7 @@ export default class Chunk {
 			let imported: string;
 			let needsLiveBinding = false;
 			if (exportName[0] === '*') {
-				const id = exportName.substr(1);
+				const id = exportName.substring(1);
 				if (interop(id) === 'defaultOnly') {
 					this.inputOptions.onwarn(errUnexpectedNamespaceReexport(id));
 				}

src/ExternalModule.ts

@@ -117,8 +117,7 @@ export default class ExternalModule {
 
 		const importersSet = new Set<string>();
 		for (const name of unused) {
-			const { importers } = this.declarations[name].module;
-			for (const importer of importers) {
+			for (const importer of this.declarations[name].module.importers) {
 				importersSet.add(importer);
 			}
 		}

src/ModuleLoader.ts

@@ -438,9 +438,8 @@ export class ModuleLoader {
 				return error(errInternalIdCannotBeExternal(source, importer));
 			}
 			return Promise.resolve(externalModule);
-		} else {
-			return this.fetchModule(resolvedId, importer, false, false);
 		}
+		return this.fetchModule(resolvedId, importer, false, false);
 	}
 
 	private async fetchStaticDependencies(
@@ -672,13 +671,11 @@ export class ModuleLoader {
 			} as ResolvedId;
 		}
 		if (resolution == null) {
-			return (module.resolvedIds[specifier] =
-				module.resolvedIds[specifier] ||
-				this.handleResolveId(
-					await this.resolveId(specifier, module.id, EMPTY_OBJECT, false),
-					specifier,
-					module.id
-				));
+			return (module.resolvedIds[specifier] ??= this.handleResolveId(
+				await this.resolveId(specifier, module.id, EMPTY_OBJECT, false),
+				specifier,
+				module.id
+			));
 		}
 		return this.handleResolveId(
 			this.getResolvedIdWithDefaults(

src/ast/nodes/MetaProperty.ts

@@ -43,7 +43,7 @@ export default class MetaProperty extends NodeBase {
 	getReferencedFileName(outputPluginDriver: PluginDriver): string | null {
 		const metaProperty = this.metaProperty as string | null;
 		if (metaProperty && metaProperty.startsWith(FILE_PREFIX)) {
-			return outputPluginDriver.getFileName(metaProperty.substr(FILE_PREFIX.length));
+			return outputPluginDriver.getFileName(metaProperty.substring(FILE_PREFIX.length));
 		}
 		return null;
 	}
@@ -91,23 +91,23 @@ export default class MetaProperty extends NodeBase {
 			let chunkReferenceId: string | null = null;
 			let fileName: string;
 			if (metaProperty.startsWith(FILE_PREFIX)) {
-				referenceId = metaProperty.substr(FILE_PREFIX.length);
+				referenceId = metaProperty.substring(FILE_PREFIX.length);
 				fileName = outputPluginDriver.getFileName(referenceId);
 			} else if (metaProperty.startsWith(ASSET_PREFIX)) {
 				warnDeprecation(
 					`Using the "${ASSET_PREFIX}" prefix to reference files is deprecated. Use the "${FILE_PREFIX}" prefix instead.`,
 					true,
 					this.context.options
 				);
-				assetReferenceId = metaProperty.substr(ASSET_PREFIX.length);
+				assetReferenceId = metaProperty.substring(ASSET_PREFIX.length);
 				fileName = outputPluginDriver.getFileName(assetReferenceId);
 			} else {
 				warnDeprecation(
 					`Using the "${CHUNK_PREFIX}" prefix to reference files is deprecated. Use the "${FILE_PREFIX}" prefix instead.`,
 					true,
 					this.context.options
 				);
-				chunkReferenceId = metaProperty.substr(CHUNK_PREFIX.length);
+				chunkReferenceId = metaProperty.substring(CHUNK_PREFIX.length);
 				fileName = outputPluginDriver.getFileName(chunkReferenceId);
 			}
 			const relativePath = normalize(relative(dirname(chunkId), fileName));

src/rollup/rollup.ts

@@ -137,12 +137,11 @@ function applyOptionHook(watchMode: boolean) {
 }
 
 function normalizePlugins(plugins: readonly Plugin[], anonymousPrefix: string): void {
-	for (let pluginIndex = 0; pluginIndex < plugins.length; pluginIndex++) {
-		const plugin = plugins[pluginIndex];
+	plugins.forEach((plugin, index) => {
 		if (!plugin.name) {
-			plugin.name = `${anonymousPrefix}${pluginIndex + 1}`;
+			plugin.name = `${anonymousPrefix}${index + 1}`;
 		}
-	}
+	});
 }
 
 async function handleGenerateWrite(

src/utils/FileEmitter.ts

@@ -42,16 +42,17 @@ function generateAssetFileName(
 				: outputOptions.assetFileNames,
 			'output.assetFileNames',
 			{
-				ext: () => extname(emittedName).substr(1),
+				ext: () => extname(emittedName).substring(1),
 				extname: () => extname(emittedName),
 				hash() {
-					const hash = createHash();
-					hash.update(emittedName);
-					hash.update(':');
-					hash.update(source);
-					return hash.digest('hex').substr(0, 8);
+					return createHash()
+						.update(emittedName)
+						.update(':')
+						.update(source)
+						.digest('hex')
+						.substring(0, 8);
 				},
-				name: () => emittedName.substr(0, emittedName.length - extname(emittedName).length)
+				name: () => emittedName.substring(0, emittedName.length - extname(emittedName).length)
 			}
 		),
 		bundle
@@ -165,7 +166,7 @@ export class FileEmitter {
 	}
 
 	public assertAssetsFinalized = (): void => {
-		for (const [referenceId, emittedFile] of this.filesByReferenceId.entries()) {
+		for (const [referenceId, emittedFile] of this.filesByReferenceId) {
 			if (emittedFile.type === 'asset' && typeof emittedFile.fileName !== 'string')
 				return error(errNoAssetSourceSet(emittedFile.name || referenceId));
 		}
@@ -241,24 +242,20 @@ export class FileEmitter {
 				reserveFileNameInBundle(emittedFile.fileName, this.bundle, this.options.onwarn);
 			}
 		}
-		for (const [referenceId, consumedFile] of this.filesByReferenceId.entries()) {
+		for (const [referenceId, consumedFile] of this.filesByReferenceId) {
 			if (consumedFile.type === 'asset' && consumedFile.source !== undefined) {
 				this.finalizeAsset(consumedFile, consumedFile.source, referenceId, this.bundle);
 			}
 		}
 	};
 
 	private assignReferenceId(file: ConsumedFile, idBase: string): string {
-		let referenceId: string | undefined;
+		let referenceId = idBase;
+
 		do {
-			const hash = createHash();
-			if (referenceId) {
-				hash.update(referenceId);
-			} else {
-				hash.update(idBase);
-			}
-			referenceId = hash.digest('hex').substr(0, 8);
+			referenceId = createHash().update(referenceId).digest('hex').substring(0, 8);
 		} while (this.filesByReferenceId.has(referenceId));
+
 		this.filesByReferenceId.set(referenceId, file);
 		return referenceId;
 	}

src/utils/PluginDriver.ts

@@ -133,7 +133,7 @@ export class PluginDriver {
 		hookName: H,
 		args: Parameters<PluginHooks[H]>,
 		replaceContext?: ReplaceContext | null,
-		skipped?: Set<Plugin> | null
+		skipped?: ReadonlySet<Plugin> | null
 	): EnsurePromise<ReturnType<PluginHooks[H]>> {
 		let promise: EnsurePromise<ReturnType<PluginHooks[H]>> = Promise.resolve(undefined as any);
 		for (const plugin of this.plugins) {

src/utils/options/normalizeOutputOptions.ts

@@ -380,9 +380,9 @@ const getInterop = (
 					errInvalidOption(
 						'output.interop',
 						'outputinterop',
-						`use one of ${Array.from(ALLOWED_INTEROP_TYPES.values(), value =>
-							JSON.stringify(value)
-						).join(', ')}`,
+						`use one of ${Array.from(ALLOWED_INTEROP_TYPES, value => JSON.stringify(value)).join(
+							', '
+						)}`,
 						interop
 					)
 				);

src/utils/relativeId.ts

@@ -2,7 +2,7 @@ import { basename, extname, isAbsolute, relative, resolve } from './path';
 
 export function getAliasName(id: string): string {
 	const base = basename(id);
-	return base.substr(0, base.length - extname(id).length);
+	return base.substring(0, base.length - extname(id).length);
 }
 
 export default function relativeId(id: string): string {

src/utils/renderNamePattern.ts

@@ -35,7 +35,7 @@ export function makeUnique(name: string, existingNames: Record<string, unknown>)
 	if (!existingNamesLowercase.has(name.toLocaleLowerCase())) return name;
 
 	const ext = extname(name);
-	name = name.substr(0, name.length - ext.length);
+	name = name.substring(0, name.length - ext.length);
 	let uniqueName: string,
 		uniqueIndex = 1;
 	while (existingNamesLowercase.has((uniqueName = name + ++uniqueIndex + ext).toLowerCase()));

src/watch/watch.ts

@@ -89,7 +89,7 @@ export class Watcher {
 
 		this.buildTimeout = setTimeout(() => {
 			this.buildTimeout = null;
-			for (const [id, event] of this.invalidatedIds.entries()) {
+			for (const [id, event] of this.invalidatedIds) {
 				this.emitter.emit('change', id, { event });
 			}
 			this.invalidatedIds.clear();