Svelte bundle.js 很大，充满@license 注释，即使在生产模式下

Question

>npm run build在一个中等规模的 Svelte 项目上生成一个大的 public/build/bundle.js 文件。Javascript 代码被最小化为一系列单行代码

function(t){return new qr((function(e){...

但在中间（或有时在中间）每一行都是许可证的大注释块

 * @license
 * Copyright 2018 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 ... 9 more lines
 * limitations under the License.

日期不同，2017-2019。还有一些 Microsoft 许可证。代码中散布着大约 70 个这样的许可证，使其膨胀到 800kb。

我没有搞乱汇总配置或任何东西。这是 package.json 相关部分：

"scripts": {
    "build": "rollup -c",
    "dev": "rollup -c -w",
    "start": "sirv public"
  },
  "devDependencies": {
    "@rollup/plugin-commonjs": "^11.0.0",
    "@rollup/plugin-node-resolve": "^7.0.0",
    "rollup": "^1.20.0",
    "rollup-plugin-livereload": "^1.0.0",
    "rollup-plugin-svelte": "^5.0.3",
    "rollup-plugin-terser": "^5.1.2",
    "svelte": "^3.0.0",
    "svelte-mui": "^0.3.3"
  },

我试过删除 node_modules 并重npm install做无效。如果这很重要，我正在 Windows 10 上运行。

Answer 1

Svelte 官方模板在生产模式 ( )下运行时使用terser进行缩小npm run build。

显然，默认情况下，terser保留许可注释（来自他们的文档）：

--comments [filter]         Preserve copyright comments in the output. By
                            default this works like Google Closure, keeping
                            JSDoc-style comments that contain "@license" or
                            "@preserve". You can optionally pass one of the
                            following arguments to this flag:
                            - "all" to keep all comments
                            - `false` to omit comments in the output
                            - a valid JS RegExp like `/foo/` or `/^!/` to
                            keep only matching comments.
                            Note that currently not *all* comments can be
                            kept when compression is on, because of dead
                            code removal or cascading statements into
                            sequences.

由于您发布的评论示例包含一个@license标签，我坚信这就是原因。

您应该能够通过将选项添加到 Rollup 配置中的 terser 插件来删除这些评论（不知道这是否合法）：

--comments [filter]         Preserve copyright comments in the output. By
                            default this works like Google Closure, keeping
                            JSDoc-style comments that contain "@license" or
                            "@preserve". You can optionally pass one of the
                            following arguments to this flag:
                            - "all" to keep all comments
                            - `false` to omit comments in the output
                            - a valid JS RegExp like `/foo/` or `/^!/` to
                            keep only matching comments.
                            Note that currently not *all* comments can be
                            kept when compression is on, because of dead
                            code removal or cascading statements into
                            sequences.