diff --git a/package.json b/package.json
index 15d30b84..dd946b71 100644
--- a/package.json
+++ b/package.json
@@ -1,11 +1,12 @@
 {
   "name": "coffee-lex",
   "description": "Stupid lexer for CoffeeScript.",
-  "main": "dist/coffee-lex.js",
-  "module": "dist/coffee-lex.mjs",
+  "main": "dist/index.js",
+  "module": "dist/index.mjs",
+  "types": "dist/index.d.ts",
   "scripts": {
     "prebuild": "rm -rf dist/",
-    "build": "rollup -c && cp src/coffee-lex.js.flow dist/",
+    "build": "./script/build",
     "lint": "tslint --config tslint.json --project tsconfig.json --type-check",
     "lint-fix": "tslint --config tslint.json --project tsconfig.json --type-check --fix",
     "pretest": "npm run lint",
@@ -37,9 +38,6 @@
     "@types/node": "^6.0.51",
     "decaffeinate-coffeescript": "^1.10.0-patch5",
     "mocha": "^3.2.0",
-    "reify": "^0.4.4",
-    "rollup": "^0.37.0",
-    "rollup-plugin-typescript": "^0.8.1",
     "semantic-release": "^6.3.2",
     "ts-node": "^1.7.2",
     "tslint": "^4.0.2",
diff --git a/rollup.config.js b/rollup.config.js
deleted file mode 100644
index 05c4fbd8..00000000
--- a/rollup.config.js
+++ /dev/null
@@ -1,21 +0,0 @@
-import ts from 'rollup-plugin-typescript';
-import * as TypeScript from 'typescript';
-
-var pkg = require('./package.json');
-
-export default {
-  entry: 'src/index.ts',
-  plugins: [ts({ typescript: TypeScript })],
-  exports: 'named',
-  targets: [
-    {
-      format: 'es',
-      dest: pkg.module
-    },
-    {
-      format: 'umd',
-      moduleName: 'coffeelex',
-      dest: pkg.main
-    }
-  ]
-};
diff --git a/script/build b/script/build
new file mode 100755
index 00000000..f404ea98
--- /dev/null
+++ b/script/build
@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+set -e
+
+DIST="${DIST:-dist}"
+TSC="${TSC:-node_modules/.bin/tsc}"
+
+# Build ES module version.
+"${TSC}" --project . --outDir "${DIST}" --module ES6
+for js in $(find "${DIST}" -name '*.js'); do
+  mv "${js}" "$(dirname "${js}")/$(basename "${js}" .js).mjs"
+done
+
+# Build CommonJS version.
+"${TSC}" --project . --outDir "${DIST}" --module commonjs
+
+# Restructure.
+rm -rf dist/test
+mv dist/src/* dist/
+rmdir dist/src
diff --git a/src/coffee-lex.js.flow b/src/coffee-lex.js.flow
deleted file mode 100644
index 8ecd6953..00000000
--- a/src/coffee-lex.js.flow
+++ /dev/null
@@ -1,211 +0,0 @@
-/* @flow */
-
-declare type SourceTokenListIndexRange = [SourceTokenListIndex, SourceTokenListIndex];
-
-declare class SourceType {
-  name: string;
-  constructor(name: string): void;
-  toString(): string;
-}
-
-declare class SourceToken {
-  type: SourceType;
-  start: number;
-  end: number;
-  constructor(type: SourceType, start: number, end: number): void;
-}
-
-declare class SourceTokenListIndex {
-  constructor(sourceTokenList: SourceTokenList, index:number): void;
-  advance(offset: number): ?SourceTokenListIndex;
-  next(): ?SourceTokenListIndex;
-  previous(): ?SourceTokenListIndex;
-  isBefore(other: SourceTokenListIndex): boolean;
-  isAfter(other: SourceTokenListIndex): boolean;
-  compare(other: SourceTokenListIndex): number;
-  distance(other: SourceTokenListIndex): number;
-}
-
-declare class SourceTokenList {
-  length: number;
-  startIndex: SourceTokenListIndex;
-  endIndex: SourceTokenListIndex;
-  constructor(tokens: Array<SourceToken>): void;
-  forEach(iterator: (token: SourceToken, index: SourceTokenListIndex, list: SourceTokenList) => void): void;
-  map<T>(mapper: (token: SourceToken, index: SourceTokenListIndex, list: SourceTokenList) => T): Array<T>;
-  filter(predicate: (token: SourceToken, index: SourceTokenListIndex, list: SourceTokenList) => boolean): SourceTokenList;
-  slice(start: SourceTokenListIndex, end: SourceTokenListIndex): SourceTokenList;
-  tokenAtIndex(index: SourceTokenListIndex): ?SourceToken;
-  rangeOfInterpolatedStringTokensContainingTokenIndex(index: SourceTokenListIndex): ?SourceTokenListIndexRange;
-  rangeOfMatchingTokensContainingTokenIndex(startType: SourceType, endType: SourceType, index: SourceTokenListIndex): ?SourceTokenListIndexRange;
-  indexOfTokenContainingSourceIndex(index: number): ?SourceTokenListIndex;
-  indexOfTokenStartingAtSourceIndex(index: number): ?SourceTokenListIndex;
-  indexOfTokenEndingAtSourceIndex(index: number): ?SourceTokenListIndex;
-  indexOfTokenMatchingPredicate(predicate: (token: SourceToken) => boolean, start?: ?SourceTokenListIndex): ?SourceTokenListIndex;
-  lastIndexOfTokenMatchingPredicate(predicate: (token: SourceToken) => boolean, start?: ?SourceTokenListIndex): ?SourceTokenListIndex;
-  toArray(): Array<SourceToken>;
-}
-
-declare class SourceLocation {
-  type: SourceType;
-  index: number;
-  constructor(type: SourceType, index: number): void;
-}
-
-declare function lex(source: string): SourceTokenList;
-declare function consumeStream(lexer: () => SourceLocation): Array<SourceLocation>;
-
-
-declare var AT: SourceType;
-declare var BOOL: SourceType;
-declare var BREAK: SourceType;
-declare var CATCH: SourceType;
-declare var CALL_END: SourceType;
-declare var CALL_START: SourceType;
-declare var CLASS: SourceType;
-declare var COLON: SourceType;
-declare var COMMA: SourceType;
-declare var COMMENT: SourceType;
-declare var CONTINUATION: SourceType;
-declare var CONTINUE: SourceType;
-declare var DELETE: SourceType;
-declare var DO: SourceType;
-declare var DOT: SourceType;
-declare var DSTRING_END: SourceType;
-declare var DSTRING_START: SourceType;
-declare var ELSE: SourceType;
-declare var EOF: SourceType;
-declare var EXISTENCE: SourceType;
-declare var FINALLY: SourceType;
-declare var FOR: SourceType;
-declare var FUNCTION: SourceType;
-declare var HERECOMMENT: SourceType;
-declare var HEREGEXP_END: SourceType;
-declare var HEREGEXP_START: SourceType;
-declare var IF: SourceType;
-declare var INTERPOLATION_START: SourceType;
-declare var INTERPOLATION_END: SourceType;
-declare var JS: SourceType;
-declare var LBRACE: SourceType;
-declare var LBRACKET: SourceType;
-declare var LOOP: SourceType;
-declare var LPAREN: SourceType;
-declare var NEWLINE: SourceType;
-declare var NORMAL: SourceType;
-declare var NULL: SourceType;
-declare var NUMBER: SourceType;
-declare var OPERATOR: SourceType;
-declare var OWN: SourceType;
-declare var PROTO: SourceType;
-declare var RANGE: SourceType;
-declare var REGEXP: SourceType;
-declare var RBRACE: SourceType;
-declare var RBRACKET: SourceType;
-declare var RELATION: SourceType;
-declare var RETURN: SourceType;
-declare var RPAREN: SourceType;
-declare var SEMICOLON: SourceType;
-declare var SPACE: SourceType;
-declare var SUPER: SourceType;
-declare var SWITCH: SourceType;
-declare var SSTRING_END: SourceType;
-declare var SSTRING_START: SourceType;
-declare var STRING_CONTENT: SourceType;
-declare var STRING_LINE_SEPARATOR: SourceType;
-declare var STRING_PADDING: SourceType;
-declare var TDSTRING_END: SourceType;
-declare var TDSTRING_START: SourceType;
-declare var THEN: SourceType;
-declare var THIS: SourceType;
-declare var TRY: SourceType;
-declare var TSSTRING_END: SourceType;
-declare var TSSTRING_START: SourceType;
-declare var UNDEFINED: SourceType;
-declare var UNKNOWN: SourceType;
-declare var WHEN: SourceType;
-declare var WHILE: SourceType;
-declare var IDENTIFIER: SourceType;
-declare var YIELD: SourceType;
-declare var YIELDFROM: SourceType;
-
-
-export {
-  lex as default,
-  consumeStream,
-  SourceLocation,
-  SourceToken,
-  SourceTokenList,
-  SourceTokenListIndex,
-  SourceType,
-  AT,
-  BOOL,
-  BREAK,
-  CATCH,
-  CALL_END,
-  CALL_START,
-  CLASS,
-  COLON,
-  COMMA,
-  COMMENT,
-  CONTINUATION,
-  CONTINUE,
-  DELETE,
-  DO,
-  DOT,
-  DSTRING_END,
-  DSTRING_START,
-  ELSE,
-  EOF,
-  EXISTENCE,
-  FINALLY,
-  FOR,
-  FUNCTION,
-  HERECOMMENT,
-  HEREGEXP_END,
-  HEREGEXP_START,
-  IF,
-  INTERPOLATION_START,
-  INTERPOLATION_END,
-  JS,
-  LBRACE,
-  LBRACKET,
-  LOOP,
-  LPAREN,
-  NEWLINE,
-  NORMAL,
-  NULL,
-  NUMBER,
-  OPERATOR,
-  OWN,
-  PROTO,
-  RANGE,
-  REGEXP,
-  RBRACE,
-  RBRACKET,
-  RELATION,
-  RETURN,
-  RPAREN,
-  SEMICOLON,
-  SPACE,
-  SUPER,
-  SWITCH,
-  SSTRING_END,
-  SSTRING_START,
-  STRING_CONTENT,
-  STRING_LINE_SEPARATOR,
-  STRING_PADDING,
-  TDSTRING_END,
-  TDSTRING_START,
-  TSSTRING_END,
-  TSSTRING_START,
-  THEN,
-  THIS,
-  TRY,
-  UNDEFINED,
-  UNKNOWN,
-  WHEN,
-  WHILE,
-  IDENTIFIER,
-  YIELD,
-  YIELDFROM,
-};
diff --git a/tsconfig.json b/tsconfig.json
index a5e1abf1..e6a5c0b9 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,11 @@
     "experimentalDecorators": true,
     "noUnusedParameters": true,
     "noUnusedLocals": true,
-    "noEmit": true
-  }
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "exclude": [
+    "node_modules",
+    "dist/**/*"
+  ]
 }
\ No newline at end of file