diff --git a/build-plugins/add-cli-entry.js b/build-plugins/add-cli-entry.ts
similarity index 83%
rename from build-plugins/add-cli-entry.js
rename to build-plugins/add-cli-entry.ts
index dbb8446c8f6..07b6d7599e1 100644
--- a/build-plugins/add-cli-entry.js
+++ b/build-plugins/add-cli-entry.ts
@@ -1,6 +1,7 @@
 import MagicString from 'magic-string';
+import { Plugin } from 'rollup';
 
-export default function addCliEntry() {
+export default function addCliEntry(): Plugin {
 	return {
 		buildStart() {
 			this.emitFile({
@@ -17,6 +18,7 @@ export default function addCliEntry() {
 				magicString.prepend('#!/usr/bin/env node\n\n');
 				return { code: magicString.toString(), map: magicString.generateMap({ hires: true }) };
 			}
+			return null;
 		}
 	};
 }
diff --git a/build-plugins/conditional-fsevents-import.js b/build-plugins/conditional-fsevents-import.ts
similarity index 91%
rename from build-plugins/conditional-fsevents-import.js
rename to build-plugins/conditional-fsevents-import.ts
index d4acf2bd3c9..5378269cf20 100644
--- a/build-plugins/conditional-fsevents-import.js
+++ b/build-plugins/conditional-fsevents-import.ts
@@ -1,9 +1,10 @@
 import MagicString from 'magic-string';
+import { Plugin } from 'rollup';
 
 const FSEVENTS_REQUIRE = "require('fsevents')";
 const REPLACEMENT = "require('../../../src/watch/fsevents-importer').getFsEvents()";
 
-export default function conditionalFsEventsImport() {
+export default function conditionalFsEventsImport(): Plugin {
 	let transformed = false;
 	return {
 		buildEnd(error) {
diff --git a/build-plugins/emit-module-package-file.js b/build-plugins/emit-module-package-file.ts
similarity index 64%
rename from build-plugins/emit-module-package-file.js
rename to build-plugins/emit-module-package-file.ts
index c6a41ddfd04..cdf5dffaff0 100644
--- a/build-plugins/emit-module-package-file.js
+++ b/build-plugins/emit-module-package-file.ts
@@ -1,4 +1,6 @@
-export default function emitModulePackageFile() {
+import { Plugin } from 'rollup';
+
+export default function emitModulePackageFile(): Plugin {
 	return {
 		generateBundle() {
 			this.emitFile({ fileName: 'package.json', source: `{"type":"module"}`, type: 'asset' });
diff --git a/build-plugins/esm-dynamic-import.js b/build-plugins/esm-dynamic-import.ts
similarity index 80%
rename from build-plugins/esm-dynamic-import.js
rename to build-plugins/esm-dynamic-import.ts
index 0e2a8e63478..3a2cfc6f18c 100644
--- a/build-plugins/esm-dynamic-import.js
+++ b/build-plugins/esm-dynamic-import.ts
@@ -1,4 +1,6 @@
-export default function addBinShebangAndEsmImport() {
+import { Plugin } from 'rollup';
+
+export default function addBinShebangAndEsmImport(): Plugin {
 	let importFound = false;
 	return {
 		generateBundle() {
diff --git a/build-plugins/generate-license-file.js b/build-plugins/generate-license-file.ts
similarity index 73%
rename from build-plugins/generate-license-file.js
rename to build-plugins/generate-license-file.ts
index 8073cf1476e..e64391c9617 100644
--- a/build-plugins/generate-license-file.js
+++ b/build-plugins/generate-license-file.ts
@@ -1,11 +1,12 @@
 import fs from 'fs';
-import license from 'rollup-plugin-license';
+import { PluginImpl } from 'rollup';
+import license, { Dependency, Person } from 'rollup-plugin-license';
 
-function generateLicenseFile(dependencies) {
+function generateLicenseFile(dependencies: Dependency[]) {
 	const coreLicense = fs.readFileSync('LICENSE-CORE.md');
 	const licenses = new Set();
 	const dependencyLicenseTexts = dependencies
-		.sort(({ name: nameA }, { name: nameB }) => (nameA > nameB ? 1 : -1))
+		.sort(({ name: nameA }, { name: nameB }) => (nameA! > nameB! ? 1 : -1))
 		.map(({ name, license, licenseText, author, maintainers, contributors, repository }) => {
 			let text = `## ${name}\n`;
 			if (license) {
@@ -15,7 +16,8 @@ function generateLicenseFile(dependencies) {
 			if (author && author.name) {
 				names.add(author.name);
 			}
-			for (const person of maintainers.concat(contributors)) {
+			// TODO there is an inconsistency in the rollup-plugin-license types
+			for (const person of contributors.concat(maintainers as unknown as Person[])) {
 				if (person && person.name) {
 					names.add(person.name);
 				}
@@ -24,7 +26,7 @@ function generateLicenseFile(dependencies) {
 				text += `By: ${Array.from(names).join(', ')}\n`;
 			}
 			if (repository) {
-				text += `Repository: ${repository.url || repository}\n`;
+				text += `Repository: ${(typeof repository === 'object' && repository.url) || repository}\n`;
 			}
 			if (licenseText) {
 				text +=
@@ -57,11 +59,14 @@ function generateLicenseFile(dependencies) {
 	}
 }
 
-export default function getLicenseHandler() {
+export default function getLicenseHandler(): {
+	collectLicenses: PluginImpl;
+	writeLicense: PluginImpl;
+} {
 	const licenses = new Map();
 	return {
 		collectLicenses() {
-			function addLicenses(dependencies) {
+			function addLicenses(dependencies: Dependency[]) {
 				for (const dependency of dependencies) {
 					licenses.set(dependency.name, dependency);
 				}
@@ -71,6 +76,7 @@ export default function getLicenseHandler() {
 		},
 		writeLicense() {
 			return {
+				name: 'write-license',
 				writeBundle() {
 					generateLicenseFile(Array.from(licenses.values()));
 				}
diff --git a/build-plugins/replace-browser-modules.js b/build-plugins/replace-browser-modules.ts
similarity index 88%
rename from build-plugins/replace-browser-modules.js
rename to build-plugins/replace-browser-modules.ts
index 9e004c5ffd9..9ffb7a8cc07 100644
--- a/build-plugins/replace-browser-modules.js
+++ b/build-plugins/replace-browser-modules.ts
@@ -1,11 +1,12 @@
 import path from 'path';
+import { Plugin } from 'rollup';
 
 const ID_CRYPTO = path.resolve('src/utils/crypto');
 const ID_FS = path.resolve('src/utils/fs');
 const ID_PATH = path.resolve('src/utils/path');
 const ID_RESOLVEID = path.resolve('src/utils/resolveId');
 
-export default function replaceBrowserModules() {
+export default function replaceBrowserModules(): Plugin {
 	return {
 		name: 'replace-browser-modules',
 		resolveId: (source, importee) => {
diff --git a/package-lock.json b/package-lock.json
index aeba1730073..9b46f6a86e1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -545,16 +545,6 @@
         "magic-string": "^0.25.7"
       }
     },
-    "@rollup/plugin-typescript": {
-      "version": "8.2.1",
-      "resolved": "https://registry.npmjs.org/@rollup/plugin-typescript/-/plugin-typescript-8.2.1.tgz",
-      "integrity": "sha512-Qd2E1pleDR4bwyFxqbjt4eJf+wB0UKVMLc7/BAFDGVdAXQMCsD4DUv5/7/ww47BZCYxWtJqe1Lo0KVNswBJlRw==",
-      "dev": true,
-      "requires": {
-        "@rollup/pluginutils": "^3.1.0",
-        "resolve": "^1.17.0"
-      }
-    },
     "@rollup/pluginutils": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/@rollup/pluginutils/-/pluginutils-3.1.0.tgz",
@@ -4243,12 +4233,12 @@
       }
     },
     "rollup": {
-      "version": "2.51.2",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.51.2.tgz",
-      "integrity": "sha512-ReV2eGEadA7hmXSzjxdDKs10neqH2QURf2RxJ6ayAlq93ugy6qIvXMmbc5cWMGCDh1h5T4thuWO1e2VNbMq8FA==",
+      "version": "2.52.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-2.52.0.tgz",
+      "integrity": "sha512-lSkBDGsVoXjqaBf7dsHwxBJz+p+hJEP72P+LOitA0yVs+Nzxj76FidkZE2thrmhjwGqLYiJo39opi7mAfaQ/Vg==",
       "dev": true,
       "requires": {
-        "fsevents": "~2.3.1"
+        "fsevents": "~2.3.2"
       }
     },
     "rollup-plugin-license": {
diff --git a/package.json b/package.json
index 1fa51617430..7546091d891 100644
--- a/package.json
+++ b/package.json
@@ -9,9 +9,9 @@
     "rollup": "dist/bin/rollup"
   },
   "scripts": {
-    "build": "shx rm -rf dist && git rev-parse HEAD > .commithash && rollup -c && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
-    "build:cjs": "shx rm -rf dist && rollup -c --configTest && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
-    "build:bootstrap": "dist/bin/rollup -c && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
+    "build": "shx rm -rf dist && git rev-parse HEAD > .commithash && rollup --config rollup.config.ts --configPlugin typescript && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
+    "build:cjs": "shx rm -rf dist && rollup --config rollup.config.ts --configPlugin typescript --configTest && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
+    "build:bootstrap": "dist/bin/rollup --config rollup.config.ts --configPlugin typescript && shx cp src/rollup/types.d.ts dist/rollup.d.ts && shx chmod a+x dist/bin/rollup",
     "ci:lint": "npm run lint:nofix",
     "ci:test": "npm run build:cjs && npm run build:bootstrap && npm run test:all",
     "ci:test:only": "npm run build:cjs && npm run build:bootstrap && npm run test:only",
@@ -38,7 +38,7 @@
     "test:only": "mocha test/test.js",
     "test:typescript": "shx rm -rf test/typescript/dist && shx cp -r dist test/typescript/ && tsc --noEmit -p test/typescript && tsc --noEmit",
     "test:browser": "mocha test/browser/index.js",
-    "watch": "rollup -cw"
+    "watch": "rollup --config rollup.config.ts --configPlugin typescript --watch"
   },
   "repository": "rollup/rollup",
   "keywords": [
@@ -64,7 +64,6 @@
     "@rollup/plugin-json": "^4.1.0",
     "@rollup/plugin-node-resolve": "^13.0.0",
     "@rollup/plugin-replace": "^2.4.2",
-    "@rollup/plugin-typescript": "^8.2.1",
     "@types/micromatch": "^4.0.1",
     "@types/node": "^10.17.60",
     "@types/require-relative": "^0.8.0",
@@ -104,7 +103,7 @@
     "pretty-ms": "^7.0.1",
     "require-relative": "^0.8.7",
     "requirejs": "^2.3.6",
-    "rollup": "^2.51.2",
+    "rollup": "^2.52.0",
     "rollup-plugin-license": "^2.5.0",
     "rollup-plugin-string": "^3.0.0",
     "rollup-plugin-terser": "^7.0.2",
diff --git a/rollup.config.js b/rollup.config.ts
similarity index 86%
rename from rollup.config.js
rename to rollup.config.ts
index 110e503a0ca..c8bedf94311 100644
--- a/rollup.config.js
+++ b/rollup.config.ts
@@ -4,15 +4,16 @@ import alias from '@rollup/plugin-alias';
 import commonjs from '@rollup/plugin-commonjs';
 import json from '@rollup/plugin-json';
 import resolve from '@rollup/plugin-node-resolve';
+import { RollupOptions, WarningHandlerWithDefault } from 'rollup';
 import { string } from 'rollup-plugin-string';
 import { terser } from 'rollup-plugin-terser';
 import typescript from 'rollup-plugin-typescript';
-import addCliEntry from './build-plugins/add-cli-entry.js';
+import addCliEntry from './build-plugins/add-cli-entry';
 import conditionalFsEventsImport from './build-plugins/conditional-fsevents-import';
-import emitModulePackageFile from './build-plugins/emit-module-package-file.js';
-import esmDynamicImport from './build-plugins/esm-dynamic-import.js';
+import emitModulePackageFile from './build-plugins/emit-module-package-file';
+import esmDynamicImport from './build-plugins/esm-dynamic-import';
 import getLicenseHandler from './build-plugins/generate-license-file';
-import replaceBrowserModules from './build-plugins/replace-browser-modules.js';
+import replaceBrowserModules from './build-plugins/replace-browser-modules';
 import pkg from './package.json';
 
 const commitHash = (function () {
@@ -24,7 +25,9 @@ const commitHash = (function () {
 })();
 
 const now = new Date(
-	process.env.SOURCE_DATE_EPOCH ? process.env.SOURCE_DATE_EPOCH * 1000 : new Date().getTime()
+	process.env.SOURCE_DATE_EPOCH
+		? 1000 * parseInt(process.env.SOURCE_DATE_EPOCH)
+		: new Date().getTime()
 ).toUTCString();
 
 const banner = `/*
@@ -37,7 +40,7 @@ const banner = `/*
 	Released under the MIT License.
 */`;
 
-const onwarn = warning => {
+const onwarn: WarningHandlerWithDefault = warning => {
 	// eslint-disable-next-line no-console
 	console.error(
 		'Building Rollup produced warnings that need to be resolved. ' +
@@ -71,9 +74,9 @@ const nodePlugins = [
 	typescript()
 ];
 
-export default command => {
+export default (command: Record<string, unknown>): RollupOptions | RollupOptions[] => {
 	const { collectLicenses, writeLicense } = getLicenseHandler();
-	const commonJSBuild = {
+	const commonJSBuild: RollupOptions = {
 		// fsevents is a dependency of chokidar that cannot be bundled as it contains binary code
 		external: [
 			'buffer',
@@ -118,7 +121,8 @@ export default command => {
 			...nodePlugins,
 			addCliEntry(),
 			esmDynamicImport(),
-			!command.configTest && collectLicenses()
+			// TODO this relied on an unpublished type update
+			(!command.configTest && collectLicenses()) as Plugin
 		],
 		strictDeprecations: true,
 		treeshake
@@ -128,7 +132,7 @@ export default command => {
 		return commonJSBuild;
 	}
 
-	const esmBuild = {
+	const esmBuild: RollupOptions = {
 		...commonJSBuild,
 		input: { 'rollup.js': 'src/node-entry.ts' },
 		output: {
@@ -141,7 +145,7 @@ export default command => {
 		plugins: [...nodePlugins, emitModulePackageFile(), collectLicenses()]
 	};
 
-	const browserBuilds = {
+	const browserBuilds: RollupOptions = {
 		input: 'src/browser-entry.ts',
 		onwarn,
 		output: [
diff --git a/src/utils/ensureArray.ts b/src/utils/ensureArray.ts
index f108c6b3454..080d73ae226 100644
--- a/src/utils/ensureArray.ts
+++ b/src/utils/ensureArray.ts
@@ -1,4 +1,6 @@
-export function ensureArray<T>(items: (T | null | undefined)[] | T | null | undefined): T[] {
+export function ensureArray<T>(
+	items: (T | false | null | undefined)[] | T | false | null | undefined
+): T[] {
 	if (Array.isArray(items)) {
 		return items.filter(Boolean) as T[];
 	}
diff --git a/src/utils/renderChunk.ts b/src/utils/renderChunk.ts
index 08a979bf61f..ac0c63e62a5 100644
--- a/src/utils/renderChunk.ts
+++ b/src/utils/renderChunk.ts
@@ -23,7 +23,7 @@ export default function renderChunk({
 }): Promise<string> {
 	const renderChunkReducer = (
 		code: string,
-		result: { code: string; map?: SourceMapInput } | string | null,
+		result: { code: string; map?: SourceMapInput } | string | null | undefined,
 		plugin: Plugin
 	): string => {
 		if (result == null) return code;
diff --git a/tsconfig.json b/tsconfig.json
index 94397632d03..bbbd924248b 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -9,10 +9,11 @@
 		"noUnusedLocals": true,
 		"noUnusedParameters": true,
 		"pretty": true,
+		"resolveJsonModule": true,
 		"skipLibCheck": true,
 		"strict": true,
 		"target": "es2018"
 	},
-	"include": ["typings/**/*.d.ts", "src", "cli", "browser"],
+	"include": ["typings/**/*.d.ts", "src", "cli", "browser", "rollup.config.ts"],
 	"exclude": ["dist", "node_modules", "test/typescript"]
 }
diff --git a/typings/declarations.d.ts b/typings/declarations.d.ts
index c32c42312d7..7e9fe302618 100644
--- a/typings/declarations.d.ts
+++ b/typings/declarations.d.ts
@@ -5,6 +5,15 @@ declare module 'help.md' {
 }
 
 // external libs
+declare module 'rollup-plugin-string' {
+	export const string: import('rollup').PluginImpl;
+}
+
+declare module 'rollup-plugin-typescript' {
+	const typescript: import('rollup').PluginImpl;
+	export default typescript;
+}
+
 declare module 'acorn-class-fields' {
 	const plugin: (BaseParser: typeof acorn.Parser) => typeof acorn.Parser;
 	export default plugin;