Added es5 builds for firestore v9 and firestore lite (#4905)

* make esm5 builds for firestore

* build cjs for node

* mangle es5 again

Author: Feiyang1

packages/firestore/exp/package.json

@@ -1,11 +1,12 @@
 {
   "name": "@firebase/firestore-exp",
   "description": "A tree-shakeable version of the Firestore SDK",
-  "main": "../dist/exp/index.node.umd.js",
+  "main": "../dist/exp/index.node.cjs.js",
   "main-esm": "../dist/exp/index.node.esm2017.js",
   "module": "../dist/exp/index.browser.esm2017.js",
   "browser": "../dist/exp/index.browser.esm2017.js",
   "react-native": "../dist/exp/index.rn.esm2017.js",
+  "esm5": "../dist/exp/index.browser.esm5.js",
   "typings": "../dist/exp/index.d.ts",
   "private": true
 }

packages/firestore/lite/package.json

@@ -1,11 +1,12 @@
 {
   "name": "@firebase/firestore-lite",
   "description": "A lite version of the Firestore SDK",
-  "main": "../dist/lite/index.node.umd.js",
+  "main": "../dist/lite/index.node.cjs.js",
   "main-esm": "../dist/lite/index.node.esm2017.js",
   "module": "../dist/lite/index.browser.esm2017.js",
   "browser": "../dist/lite/index.browser.esm2017.js",
   "react-native": "../dist/lite/index.rn.esm2017.js",
+  "esm5": "../dist/lite/index.browser.esm5.js",
   "typings": "../dist/lite/index.d.ts",
   "private": true
 }

packages/firestore/rollup.config.exp.js

@@ -97,13 +97,12 @@ const allBuilds = [
     },
     onwarn: util.onwarn
   },
-  // Node UMD build
+  // Node CJS build
   {
     input: path.resolve('./exp', pkg['main-esm']),
     output: {
       file: path.resolve('./exp', pkg.main),
-      format: 'umd',
-      name: 'firebase.firestore',
+      format: 'cjs',
       sourcemap: true
     },
     plugins: util.es2017ToEs5Plugins(/* mangled= */ false),
@@ -126,6 +125,22 @@ const allBuilds = [
       moduleSideEffects: false
     }
   },
+  // Convert es2017 build to ES5
+  {
+    input: path.resolve('./exp', pkg['browser']),
+    output: [
+      {
+        file: path.resolve('./exp', pkg['esm5']),
+        format: 'es',
+        sourcemap: true
+      }
+    ],
+    plugins: util.es2017ToEs5Plugins(/* mangled= */ true),
+    external: util.resolveBrowserExterns,
+    treeshake: {
+      moduleSideEffects: false
+    }
+  },
   // RN build
   {
     input: './exp/index.rn.ts',

packages/firestore/rollup.config.lite.js

@@ -96,13 +96,12 @@ const allBuilds = [
     },
     onwarn: util.onwarn
   },
-  // Node UMD build
+  // Node CJS build
   {
     input: path.resolve('./lite', pkg['main-esm']),
     output: {
       file: path.resolve('./lite', pkg.main),
-      format: 'umd',
-      name: 'firebase.firestore',
+      format: 'cjs',
       sourcemap: true
     },
     plugins: [
@@ -139,6 +138,22 @@ const allBuilds = [
       moduleSideEffects: false
     }
   },
+  // Convert es2017 build to ES5
+  {
+    input: path.resolve('./lite', pkg.browser),
+    output: [
+      {
+        file: path.resolve('./lite', pkg.esm5),
+        format: 'es',
+        sourcemap: true
+      }
+    ],
+    plugins: util.es2017ToEs5Plugins(/* mangled= */ true),
+    external: util.resolveBrowserExterns,
+    treeshake: {
+      moduleSideEffects: false
+    }
+  },
   // RN build
   {
     input: './lite/index.ts',