Webpack 4迁移CommonsChunkPlugin

Question

我需要帮助将以下代码从webpack 3迁移到4.

new webpack.optimize.CommonsChunkPlugin({
    minChunks: module => module.context && module.context.indexOf("node_modules") !== -1,
    name: "vendor",
    chunks: ["main"]
})

我有两个条目文件,只希望第一个的依赖项包含在供应商块中.第二个条目的依赖关系应该都保留在自己的bundle中.

Answer 1

从webpack v4开始,CommonsChunkPlugin已被弃用.

我们已经弃用并删除了CommonsChunkPlugin,并将其替换为一组默认值和易于覆盖的API optimization.splitChunks.

webpack.optimize.CommonsChunkPlugin has been removed, 
please use config.optimization.splitChunks instead.

弃用

您不再需要使用这些插件:

DedupePlugin在v4中也被删除了

NoEmitOnErrorsPlugin - > optimization.noEmitOnErrors(由在生产模式默认) ModuleConcatenationPlugin - > optimization.concatenateModules(由在PROD模式默认) NamedModulesPlugin - > optimization.namedModules(默认情况下在开发者模式)

webpack的建议4

用mini-css-extract-plugin而不是text-extract-plugin.用于webpack-bundle-analyzer以图形方式分析捆绑的输出.

进入脚本是真正的"入门脚本"您的应用程序,没有供应商的文件添加明确地entry:在webpack.config.js.SPA应用程序有一个条目,而像经典ASP.NET MVC应用程序这样的多页面应用程序有多个入口点.Webpack将根据您的条目脚本构建一个依赖图,并为您的应用生成优化的捆绑包.

如果要从较旧的Webpack版本迁移,最好查看迁移指南

树摇动(死代码消除)仅在生产模式下启用.

Webpack 4,捆绑资产的新方式

(你必须从头脑中删除你的CommonsChunkPlugin)

!同时webpack文档已经更新,SplitChunks增加了一个部分!

它遵循一种新的理念:

默认情况下,Webpack 4现在会自动执行优化.它根据以下条件分析您的依赖关系图并创建最佳的包(输出):

1. 新块可以共享,或者模块来自node_modules文件夹
2. 新块将大于30kb(在min + gz之前)
3. 根据需要加载块时的最大并行请求数<= 5
4. 初始页面加载时的最大并行请求数<= 3

所有这些都可以使用SplitChunksPlugin进行调整!(参见SplitChunksPlugin文档)

有关如何使用新optimization.splitChunksAPI的更详细说明.

CommonsChunkPlugin被删除,因为它有很多问题:

• 它可能导致下载的代码多于所需的代码.
• 它在异步块上效率低下.
• 这很难使用.
• 实施很难理解.

SplitChunksPlugin还有一些很棒的属性:

• 它永远不会下载不需要的模块(只要你不通过名称强制执行块合并)
• 它也可以在异步块上高效工作
• 它默认为异步块
• 它使用多个供应商块来处理供应商拆分
• 它更容易使用
• 它不依赖于块图黑客
• 大多是自动的

- >来源

关于您的问题,您希望将entry1和entry2的所有deps拆分为单独的bundle.

      optimization: {
        splitChunks: {
          cacheGroups: {   
            "entry1-bundle": {
              test: /.../,   // <-- use the test property to specify which deps go here
              chunks: "all",
              name: "entry1-bundle",
 /** Ignore minimum size, minimum chunks and maximum requests and always create chunks for this cache group */
              enforce: true,
              priority: ..  // use the priority, to tell where a shared dep should go
            },
            "entry2-bundle": {
              test: /..../, // <-- use the test property to specify which deps go here
              chunks: "all",
              name: "entry2-bundle",
              enforce: true,
              priority: ..
            }
          }
        }
      },

如果不添加优化:splitChunks条目,则默认设置如下:

splitChunks: {
  chunks: 'async',
  minSize: 30000,
  minRemainingSize: 0,
  maxSize: 0,
  minChunks: 1,
  maxAsyncRequests: 6,
  maxInitialRequests: 4,
  automaticNameDelimiter: '~',
  automaticNameMaxLength: 30,
  cacheGroups: {
    vendors: {
      test: /[\\/]node_modules[\\/]/,
      priority: -10
    },
    default: {
      minChunks: 2,
      priority: -20,
      reuseExistingChunk: true
    }
  }
}

您可以设置optimization.splitChunks.cacheGroups.默认为false以禁用默认缓存组,对于供应商缓存组也是如此!

截至到最新的接口实现的SplitChunksOptions,CachGroupOptions并且Optimization可以发现在这里.

下面的接口定义可能不是100%准确,但对于简单的概述很有用:

SplitChunksOptions 接口

interface SplitChunksOptions {
    /** Select chunks for determining shared modules (defaults to \"async\", \"initial\" and \"all\" requires adding these chunks to the HTML) */
    chunks?: "initial" | "async" | "all" | ((chunk: compilation.Chunk) => boolean);
    /** Minimal size for the created chunk */
    minSize?: number;
    /** Minimum number of times a module has to be duplicated until it's considered for splitting */
    minChunks?: number;
    /** Maximum number of requests which are accepted for on-demand loading */
    maxAsyncRequests?: number;
    /** Maximum number of initial chunks which are accepted for an entry point */
    maxInitialRequests?: number;
    /** Give chunks created a name (chunks with equal name are merged) */
    name?: boolean | string | ((...args: any[]) => any);
    /** Assign modules to a cache group (modules from different cache groups are tried to keep in separate chunks) */
    cacheGroups?: false | string | ((...args: any[]) => any) | RegExp | { [key: string]: CacheGroupsOptions };
}

CacheGroupsOptions 接口:

interface CacheGroupsOptions {
    /** Assign modules to a cache group */
    test?: ((...args: any[]) => boolean) | string | RegExp;
    /** Select chunks for determining cache group content (defaults to \"initial\", \"initial\" and \"all\" requires adding these chunks to the HTML) */
    chunks?: "initial" | "async" | "all" | ((chunk: compilation.Chunk) => boolean);
    /** Ignore minimum size, minimum chunks and maximum requests and always create chunks for this cache group */
    enforce?: boolean;
    /** Priority of this cache group */
    priority?: number;
    /** Minimal size for the created chunk */
    minSize?: number;
    /** Minimum number of times a module has to be duplicated until it's considered for splitting */
    minChunks?: number;
    /** Maximum number of requests which are accepted for on-demand loading */
    maxAsyncRequests?: number;
    /** Maximum number of initial chunks which are accepted for an entry point */
    maxInitialRequests?: number;
    /** Try to reuse existing chunk (with name) when it has matching modules */
    reuseExistingChunk?: boolean;
    /** Give chunks created a name (chunks with equal name are merged) */
    name?: boolean | string | ((...args: any[]) => any);
}

Optimization 接口

interface Optimization {
    /**
     *  Modules are removed from chunks when they are already available in all parent chunk groups.
     *  This reduces asset size. Smaller assets also result in faster builds since less code generation has to be performed.
     */
    removeAvailableModules?: boolean;
    /** Empty chunks are removed. This reduces load in filesystem and results in faster builds. */
    removeEmptyChunks?: boolean;
    /** Equal chunks are merged. This results in less code generation and faster builds. */
    mergeDuplicateChunks?: boolean;
    /** Chunks which are subsets of other chunks are determined and flagged in a way that subsets don’t have to be loaded when the bigger chunk has been loaded. */
    flagIncludedChunks?: boolean;
    /** Give more often used ids smaller (shorter) values. */
    occurrenceOrder?: boolean;
    /** Determine exports for each module when possible. This information is used by other optimizations or code generation. I. e. to generate more efficient code for export * from. */
    providedExports?: boolean;
    /**
     *  Determine used exports for each module. This depends on optimization.providedExports. This information is used by other optimizations or code generation.
     *  I. e. exports are not generated for unused exports, export names are mangled to single char identifiers when all usages are compatible.
     *  DCE in minimizers will benefit from this and can remove unused exports.
     */
    usedExports?: boolean;
    /**
     *  Recognise the sideEffects flag in package.json or rules to eliminate modules. This depends on optimization.providedExports and optimization.usedExports.
     *  These dependencies have a cost, but eliminating modules has positive impact on performance because of less code generation. It depends on your codebase.
     *  Try it for possible performance wins.
     */
    sideEffects?: boolean;
    /** Tries to find segments of the module graph which can be safely concatenated into a single module. Depends on optimization.providedExports and optimization.usedExports. */
    concatenateModules?: boolean;
    /** Finds modules which are shared between chunk and splits them into separate chunks to reduce duplication or separate vendor modules from application modules. */
    splitChunks?: SplitChunksOptions | false;
    /** Create a separate chunk for the webpack runtime code and chunk hash maps. This chunk should be inlined into the HTML */
    runtimeChunk?: boolean | "single" | "multiple" | RuntimeChunkOptions;
    /** Avoid emitting assets when errors occur. */
    noEmitOnErrors?: boolean;
    /** Instead of numeric ids, give modules readable names for better debugging. */
    namedModules?: boolean;
    /** Instead of numeric ids, give chunks readable names for better debugging. */
    namedChunks?: boolean;
    /** Defines the process.env.NODE_ENV constant to a compile-time-constant value. This allows to remove development only code from code. */
    nodeEnv?: string | false;
    /** Use the minimizer (optimization.minimizer, by default uglify-js) to minimize output assets. */
    minimize?: boolean;
    /** Minimizer(s) to use for minimizing the output */
    minimizer?: Array<Plugin | Tapable.Plugin>;
    /** Generate records with relative paths to be able to move the context folder". */
    portableRecords?: boolean;
}
}

Answer 2

我有两个条目文件,只希望第一个的依赖项包含在供应商块中.第二个条目的依赖关系应该都保留在自己的bundle中.

假设您的入口点是main和secondary:

entry: {
    main: 'path-to/main.js',
    secondary: 'path-to/secondary.js'
}

使用webpack-4您可以仅从块中提取vendors模块,main但secondary使用您要创建的test功能将其他第三方模块保留在该块中cacheGroups.

optimization: {
    splitChunks: {
        cacheGroups: {
            vendors: {
                name: 'vendors',
                chunks: 'all',
                reuseExistingChunk: true,
                priority: 1,
                enforce: true,
                test(module, chunks) {
                    const name = module.nameForCondition && module.nameForCondition();
                    return chunks.some(chunk => {
                        return chunk.name === 'main' && /[\\/]node_modules[\\/]/.test(name);
                    });
                }
            },
            secondary: {
                name: 'secondary',
                chunks: 'all',
                priority: 2,
                enforce: true,
                test(module, chunks) {
                    return chunks.some(chunk => chunk.name === 'secondary');
                }
            }
        }
    }
}