Adding rollup es5 step

Author: hsubox76

packages/webchannel-wrapper/gulpfile.js

@@ -24,6 +24,9 @@ const sourcemaps = require('gulp-sourcemaps');
 const { resolve } = require('path');
 const commonjs = require('rollup-plugin-commonjs');
 const rollupSourcemaps = require('rollup-plugin-sourcemaps');
+const { terser } = require('rollup-plugin-terser');
+const typescriptPlugin = require('rollup-plugin-typescript2');
+const typescript = require('typescript');
 
 // The optimization level for the JS compiler.
 // Valid levels: WHITESPACE_ONLY, SIMPLE_OPTIMIZATIONS, ADVANCED_OPTIMIZATIONS.
@@ -95,7 +98,16 @@ function createRollupTask(inputPath, outputExtension) {
   return async function rollupBuild() {
     const inputOptions = {
       input: inputPath,
-      plugins: [rollupSourcemaps(), commonjs()]
+      plugins: [
+        rollupSourcemaps(),
+        commonjs(),
+        typescriptPlugin({
+          typescript,
+          compilerOptions: { allowJs: true, include: [inputPath], target: "ES5" },
+          input: inputPath
+        }),
+        terser()
+      ]
     };
 
     const outputOptions = {
@@ -126,7 +138,7 @@ gulp.task('cjs', cjsBuild);
 // 2) Use rollup to convert result to ESM format.
 const intermediateEsmFile = 'temp/esm.js';
 const intermediateEsmPath = resolve(__dirname, 'dist/', intermediateEsmFile);
-const esmBuild = createBuildTask(intermediateEsmFile, '', '');
+const esmBuild = createBuildTask(intermediateEsmFile, '', '', 'ECMASCRIPT_2017');
 const rollupTask = createRollupTask(intermediateEsmPath, 'esm');
 gulp.task('esm', gulp.series(esmBuild, rollupTask));
 

packages/webchannel-wrapper/package.json

@@ -16,13 +16,15 @@
   },
   "license": "Apache-2.0",
   "devDependencies": {
-    "google-closure-compiler": "20200112.0.0",
-    "google-closure-library": "20200112.0.0",
+    "google-closure-compiler": "20200204.0.0",
+    "google-closure-library": "20200204.0.0",
     "gulp": "4.0.2",
     "gulp-sourcemaps": "2.6.5",
     "rollup": "2.6.1",
     "rollup-plugin-commonjs": "10.1.0",
-    "rollup-plugin-sourcemaps": "0.5.0"
+    "rollup-plugin-sourcemaps": "0.5.0",
+    "rollup-plugin-terser": "5.3.0",
+    "rollup-plugin-typescript2": "0.27.0"
   },
   "repository": {
     "directory": "packages/webchannel-wrapper",

packages/webchannel-wrapper/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../../config/tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "dist"
+  },
+  "exclude": [
+    "dist/**/*"
+  ]
+}