From 627027fd4351c1a6fa4926765c805165a56d7818 Mon Sep 17 00:00:00 2001
From: ziga <zigomir@gmail.com>
Date: Wed, 10 Apr 2019 21:49:12 -0400
Subject: [PATCH] feat(esm build): build ES modules for browser (#2705)

---
 build/build.js   | 18 ++++++++++--------
 build/configs.js | 19 +++++++++++++++++--
 package.json     |  2 +-
 yarn.lock        |  4 ++--
 4 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/build/build.js b/build/build.js
index fe374587c..09767b9e6 100644
--- a/build/build.js
+++ b/build/build.js
@@ -1,7 +1,7 @@
 const fs = require('fs')
 const path = require('path')
 const zlib = require('zlib')
-const uglify = require('uglify-js')
+const terser = require('terser')
 const rollup = require('rollup')
 const configs = require('./configs')
 
@@ -27,22 +27,24 @@ function build (builds) {
 }
 
 function buildEntry ({ input, output }) {
-  const isProd = /min\.js$/.test(output.file)
+  const { file, banner } = output
+  const isProd = /min\.js$/.test(file)
   return rollup.rollup(input)
     .then(bundle => bundle.generate(output))
     .then(({ code }) => {
       if (isProd) {
-        const minified = uglify.minify(code, {
+        const minified = (banner ? banner + '\n' : '') + terser.minify(code, {
+          toplevel: true,
           output: {
-            preamble: output.banner,
-            /* eslint-disable camelcase */
             ascii_only: true
-            /* eslint-enable camelcase */
+          },
+          compress: {
+            pure_funcs: ['makeMap']
           }
         }).code
-        return write(output.file, minified, true)
+        return write(file, minified, true)
       } else {
-        return write(output.file, code)
+        return write(file, code)
       }
     })
 }
diff --git a/build/configs.js b/build/configs.js
index f81ec3a93..67371b8e2 100644
--- a/build/configs.js
+++ b/build/configs.js
@@ -33,6 +33,18 @@ module.exports = [
   {
     file: resolve('dist/vue-router.esm.js'),
     format: 'es'
+  },
+  {
+    file: resolve('dist/vue-router.esm.browser.js'),
+    format: 'es',
+    env: 'development',
+    transpile: false
+  },
+  {
+    file: resolve('dist/vue-router.esm.browser.min.js'),
+    format: 'es',
+    env: 'production',
+    transpile: false
   }
 ].map(genConfig)
 
@@ -46,8 +58,7 @@ function genConfig (opts) {
         cjs(),
         replace({
           __VERSION__: version
-        }),
-        buble()
+        })
       ]
     },
     output: {
@@ -64,5 +75,9 @@ function genConfig (opts) {
     }))
   }
 
+  if (opts.transpile !== false) {
+    config.input.plugins.push(buble())
+  }
+
   return config
 }
diff --git a/package.json b/package.json
index 635a78823..525f8e6d1 100644
--- a/package.json
+++ b/package.json
@@ -82,8 +82,8 @@
     "rollup-plugin-replace": "^2.0.0",
     "rollup-watch": "^4.0.0",
     "selenium-server": "^2.53.1",
+    "terser": "^3.17.0",
     "typescript": "^3.3.1",
-    "uglify-js": "^3.3.13",
     "vue": "^2.5.16",
     "vue-loader": "^15.2.1",
     "vue-template-compiler": "^2.5.16",
diff --git a/yarn.lock b/yarn.lock
index 27f99a012..897c945cb 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -9828,7 +9828,7 @@ terser-webpack-plugin@^1.1.0:
     webpack-sources "^1.1.0"
     worker-farm "^1.5.2"
 
-terser@^3.16.1:
+terser@^3.16.1, terser@^3.17.0:
   version "3.17.0"
   resolved "https://registry.yarnpkg.com/terser/-/terser-3.17.0.tgz#f88ffbeda0deb5637f9d24b0da66f4e15ab10cb2"
   integrity sha512-/FQzzPJmCpjAH9Xvk2paiWrFq+5M6aVOf+2KRbwhByISDX/EujxsK+BAvrhb6H+2rtrLCHK9N01wO014vrIwVQ==
@@ -10078,7 +10078,7 @@ uglify-js@3.4.x:
     commander "~2.19.0"
     source-map "~0.6.1"
 
-uglify-js@^3.1.4, uglify-js@^3.3.13:
+uglify-js@^3.1.4:
   version "3.4.9"
   resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.4.9.tgz#af02f180c1207d76432e473ed24a28f4a782bae3"
   integrity sha512-8CJsbKOtEbnJsTyv6LE6m6ZKniqMiFWmm9sRbopbkGs3gMPPfd3Fh8iIA4Ykv5MgaTbqHr4BaoGLJLZNhsrW1Q==