fix: restore default export for backwards compat

Brings back default exports for backwards compatibility, but this time in a way that works with AMD and CJS module formats without build tool hacks. Uses rollup-plugin-dts to generate the type declaration for the bundle output, removing the brittle regex-based wrangling we were doing.

package.json

@@ -3,7 +3,7 @@
 	"description": "Super simple, fast and easy to use tweening engine which incorporates optimised Robert Penner's equations.",
 	"version": "18.6.0",
 	"main": "dist/tween.cjs.js",
-	"types": "dist/index.d.ts",
+	"types": "dist/tween.d.ts",
 	"module": "dist/tween.esm.js",
 	"files": [
 		"dist",
@@ -25,12 +25,10 @@
 	],
 	"dependencies": {},
 	"scripts": {
-		"build": "rimraf dist && rimraf .tmp && node scripts/write-version.js && npm run tsc && npm run rollup-build && npm run tsc-d.ts && npm run adjust-d.ts",
+		"build": "rimraf dist .tmp && node scripts/write-version.js && npm run tsc && npm run rollup-build",
 		"rollup-build": "rollup -c ./rollup.config.js",
 		"tsc": "tsc",
 		"tsc-watch": "tsc --watch",
-		"tsc-d.ts": "tsc --declaration --emitDeclarationOnly --esModuleInterop --outFile dist/index.d.ts",
-		"adjust-d.ts": "node scripts/adjust-d.ts.js",
 		"test": "npm run build && npm run test-unit && npm run test-lint",
 		"test-unit": "nodeunit test/unit/nodeunitheadless.js",
 		"test-lint": "npm run prettier -- --check && eslint 'src/**/*.ts'",
@@ -52,7 +50,8 @@
 		"nodeunit": "^0.11.3",
 		"prettier": "^2.0.0",
 		"rimraf": "^3.0.0",
-		"rollup": "^0.57.1",
+		"rollup": "^2.0.0",
+		"rollup-plugin-dts": "1.4.10",
 		"tslib": "^1.10.0",
 		"typescript": "^4.0.0"
 	}

rollup.config.js

@@ -1,24 +1,33 @@
-export default {
-	input: '.tmp/Index.js',
-	// https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined
-	context: 'this',
-	output: [
-		{
-			file: 'dist/tween.umd.js',
-			name: 'TWEEN',
-			format: 'umd',
-		},
-		{
-			file: 'dist/tween.amd.js',
-			format: 'amd',
-		},
-		{
-			file: 'dist/tween.cjs.js',
-			format: 'cjs',
-		},
-		{
-			file: 'dist/tween.esm.js',
-			format: 'es',
-		},
-	],
-}
+import dts from 'rollup-plugin-dts'
+
+export default [
+	{
+		input: '.tmp/Index.js',
+		// https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined
+		context: 'this',
+		output: [
+			{
+				file: 'dist/tween.umd.js',
+				name: 'TWEEN',
+				format: 'umd',
+			},
+			{
+				file: 'dist/tween.amd.js',
+				format: 'amd',
+			},
+			{
+				file: 'dist/tween.cjs.js',
+				format: 'cjs',
+			},
+			{
+				file: 'dist/tween.esm.js',
+				format: 'es',
+			},
+		],
+	},
+	{
+		input: './.tmp/Index.d.ts',
+		output: [{file: 'dist/tween.d.ts', format: 'es'}],
+		plugins: [dts()],
+	},
+]