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浅析webpack源码之Compilation.js粗解(九)

Tangpj / 1328人阅读

摘要:编写良好的模块提供了可靠的抽象和封装边界,构成了一致的设计和明确的目的。块此特定术语在内部用于管理捆绑过程。捆绑包由块组成,其中有几种类型例如入口和子。总结一个块是进程中的一组模块,一个是一个发出的块或一组块。

我们先看一下 compilation是什么?
是一个很大的对象
打印key值

[ "_pluginCompat",
  "hooks",
  "name",
  "compiler",
  "resolverFactory",
  "inputFileSystem",
  "requestShortener",
  "options",
  "outputOptions",
  "bail",
  "profile",
  "performance",
  "mainTemplate",
  "chunkTemplate",
  "hotUpdateChunkTemplate",
  "runtimeTemplate",
  "moduleTemplates",
  "semaphore",
  "entries",
  "_preparedEntrypoints",
  "entrypoints",
  "chunks",
  "chunkGroups",
  "namedChunkGroups",
  "namedChunks",
  "modules",
  "_modules",
  "cache",
  "records",
  "additionalChunkAssets",
  "assets",
  "errors",
  "warnings",
  "children",
  "dependencyFactories",
  "dependencyTemplates",
  "childrenCounters",
  "usedChunkIds",
  "usedModuleIds",
  "fileTimestamps",
  "contextTimestamps",
  "compilationDependencies",
  "_buildingModules",
  "_rebuildingModules"

我们看有熟悉的chunks,entries,options,
这些是Compilation定义的属性

const EntryModuleNotFoundError = require("./EntryModuleNotFoundError");
const ModuleNotFoundError = require("./ModuleNotFoundError");
const ModuleDependencyWarning = require("./ModuleDependencyWarning");
const ModuleDependencyError = require("./ModuleDependencyError");
const ChunkGroup = require("./ChunkGroup");
const Chunk = require("./Chunk");
const Entrypoint = require("./Entrypoint");
const MainTemplate = require("./MainTemplate");
const ChunkTemplate = require("./ChunkTemplate");
const HotUpdateChunkTemplate = require("./HotUpdateChunkTemplate");
const ModuleTemplate = require("./ModuleTemplate");
const RuntimeTemplate = require("./RuntimeTemplate");
const ChunkRenderError = require("./ChunkRenderError");
const AsyncDependencyToInitialChunkError = require("./AsyncDependencyToInitialChunkError");
const Stats = require("./Stats");
const Semaphore = require("./util/Semaphore");
const createHash = require("./util/createHash");
const Queue = require("./util/Queue");
const SortableSet = require("./util/SortableSet");
const GraphHelpers = require("./GraphHelpers");
const ModuleDependency = require("./dependencies/ModuleDependency");
const compareLocations = require("./compareLocations");

从这一堆的模块引入里,也可以猜出Compilation主要做了Modules变成Chunks编译的过程

里面有一些方法

1.对模块的处理,创建搜索添加构建/模块依赖处理,添加模块依赖,分类模块等
addModule/getModule/ findModule/buildModule/sortModules
2.对Chunk的处理,创建Chunk
3.哈希值

Compilation.prototype.applyPlugins

在原型上添加了applyPlugins方法

Compilation.js也是对Tapable 的拓展
主要处理Chunk、Module等

我们学习一下

webpack术语表定义

模块:离散的功能块,提供比完整程序更小的表面积。编写良好的模块提供了可靠的抽象和封装边界,构成了一致的设计和明确的目的。

块:此Webpack特定术语在内部用于管理捆绑过程。捆绑包由块组成,其中有几种类型(例如入口和子)。通常,块直接与输出束相对应,但是,有些配置不会产生一对一的关系。

Bundle:由许多不同的模块生成,bundle包含已经过加载和编译过程的源文件的最终版本。

总结
a chunk is a group of modules within the webpack process, a bundle is an emitted chunk or set of chunks.

一个块是webpack进程中的一组模块,一个bundle是一个发出的块或一组块。

{
  entry: {
    foo: ["webpack/hot/only-dev-server.js","./src/foo.js"],
    bar: ["./src/bar.js"]
  },
  output: {
    path: "./dist",
    filename: "[name].js"
  }
}
Modules: "webpack/hot/only-dev-server.js", "./src/foo.js", "./src/bar.js" ( + any other modules that are dependencies of these entry points!)
Chunks: foo, bar
Bundles: foo, bar

通俗的解释一下,Modules是引入的模块,Chunks就是编译的模块,Bundles是提交的Chunks ,Chunks和Bundles是1:1的关系,配置map会有例外

总结

Compilation主要做了Modules变成Chunks编译的过程

chunks

不细看逻辑,好像太虚了,我们看一下this.chunks

它是一个数组,目前Chunk的长度是1,因为只是引入了一个模块

[ Chunk {
    id: "main",
    ids: [ "main" ],
    debugId: 1000,
    name: "main",
    preventIntegration: false,
    entryModule:
     NormalModule {
       dependencies: [],
       blocks: [],
       variables: [],
       type: "javascript/auto",
       context: "/Users/orion/Desktop/react-beauty-highcharts/src",
       debugId: 1000,
       hash: "a6388d29fa15bd58c6cffb10246992a5",
       renderedHash: "a6388d29fa15bd58c6cf",
       resolveOptions: {},
       factoryMeta: {},
       warnings: [],
       errors: [],
       buildMeta: [Object],
       buildInfo: [Object],
       reasons: [Array],
       _chunks: [SortableSet],
       id: "./src/index.js",
       index: 0,
       index2: 0,
       depth: 0,
       issuer: null,
       profile: undefined,
       prefetched: false,
       built: true,
       used: null,
       usedExports: null,
       optimizationBailout: [],
       _rewriteChunkInReasons: undefined,
       useSourceMap: true,
       _source: [SourceMapSource],
       request:
        "/Users/orion/Desktop/react-beauty-highcharts/node_modules/babel-loader/lib/index.js!/Users/orion/Desktop/react-beauty-highcharts/src/index.js",
       userRequest: "/Users/orion/Desktop/react-beauty-highcharts/src/index.js",
       rawRequest: "./src/index.js",
       binary: false,
       parser: [Parser],
       generator: JavascriptGenerator {},
       resource: "/Users/orion/Desktop/react-beauty-highcharts/src/index.js",
       matchResource: undefined,
       loaders: [Array],
       error: null,
       _buildHash: "488efbd43aa05371d3f44d94c89abd57",
       buildTimestamp: 1547884969828,
       _cachedSources: Map {},
       lineToLine: false,
       _lastSuccessfulBuildMeta: [Object],
       _ast: null },
    _modules:
     SortableSet [Set] {
       [NormalModule],
       _sortFn: [Function: sortByIdentifier],
       _lastActiveSortFn: null,
       _cache: undefined,
       _cacheOrderIndependent: undefined },
    filenameTemplate: undefined,
    _groups:
     SortableSet [Set] {
       [Entrypoint],
       _sortFn: [Function: sortChunkGroupById],
       _lastActiveSortFn: null,
       _cache: undefined,
       _cacheOrderIndependent: undefined },
    files: [],
    rendered: false,
    hash: "0988e8454f1915ec05fee482db8d0a6f",
    contentHash: { javascript: "4b8695ca3c1d42e76c52" },
    renderedHash: "0988e8454f1915ec05fe",
    chunkReason: undefined,
    extraAsync: false,
    removedModules: undefined } ]

我们看到在entryModule下,记录了入口的绝对地址,相对地址,编译的hash,文件类型等信息

//文件写入,文件输出,文件缓存,里面具体的template.getRenderManifest,chunk.hasRuntime(),CachedSource具体的逻辑不能够一一的去研究详解,但是从名字能知道这个函数是做什么的
createChunkAssets() {
        const outputOptions = this.outputOptions;
        const cachedSourceMap = new Map();
        /** @type {Map} */
        const alreadyWrittenFiles = new Map();
        for (let i = 0; i < this.chunks.length; i++) {
            const chunk = this.chunks[i];
            chunk.files = [];
            let source;
            let file;
            let filenameTemplate;
            try {
                const template = chunk.hasRuntime()
                    ? this.mainTemplate
                    : this.chunkTemplate;
                const manifest = template.getRenderManifest({
                    chunk,
                    hash: this.hash,
                    fullHash: this.fullHash,
                    outputOptions,
                    moduleTemplates: this.moduleTemplates,
                    dependencyTemplates: this.dependencyTemplates
                }); // [{ render(), filenameTemplate, pathOptions, identifier, hash }]
                for (const fileManifest of manifest) {
                    const cacheName = fileManifest.identifier;
                    const usedHash = fileManifest.hash;
                    filenameTemplate = fileManifest.filenameTemplate;
                    file = this.getPath(filenameTemplate, fileManifest.pathOptions);

                    // check if the same filename was already written by another chunk
                    const alreadyWritten = alreadyWrittenFiles.get(file);
                    if (alreadyWritten !== undefined) {
                        if (alreadyWritten.hash === usedHash) {
                            if (this.cache) {
                                this.cache[cacheName] = {
                                    hash: usedHash,
                                    source: alreadyWritten.source
                                };
                            }
                            chunk.files.push(file);
                            this.hooks.chunkAsset.call(chunk, file);
                            continue;
                        } else {
                            throw new Error(
                                `Conflict: Multiple chunks emit assets to the same filename ${file}` +
                                    ` (chunks ${alreadyWritten.chunk.id} and ${chunk.id})`
                            );
                        }
                    }
                    if (
                        this.cache &&
                        this.cache[cacheName] &&
                        this.cache[cacheName].hash === usedHash
                    ) {
                        source = this.cache[cacheName].source;
                    } else {
                        source = fileManifest.render();
                        // Ensure that source is a cached source to avoid additional cost because of repeated access
                        if (!(source instanceof CachedSource)) {
                            const cacheEntry = cachedSourceMap.get(source);
                            if (cacheEntry) {
                                source = cacheEntry;
                            } else {
                                const cachedSource = new CachedSource(source);
                                cachedSourceMap.set(source, cachedSource);
                                source = cachedSource;
                            }
                        }
                        if (this.cache) {
                            this.cache[cacheName] = {
                                hash: usedHash,
                                source
                            };
                        }
                    }
                    if (this.assets[file] && this.assets[file] !== source) {
                        throw new Error(
                            `Conflict: Multiple assets emit to the same filename ${file}`
                        );
                    }
                    this.assets[file] = source;
                    chunk.files.push(file);
                    this.hooks.chunkAsset.call(chunk, file);
                    alreadyWrittenFiles.set(file, {
                        hash: usedHash,
                        source,
                        chunk
                    });
                }
            } catch (err) {
                this.errors.push(
                    new ChunkRenderError(chunk, file || filenameTemplate, err)
                );
            }
        }
    }
modules
[ {
    dependencies: [],
    blocks: [],
    variables: [],
    type: "javascript/auto",
    context: "/Users/orion/Desktop/react-beauty-highcharts/src",
    debugId: 1000,
    hash: "a6388d29fa15bd58c6cffb10246992a5",
    renderedHash: "a6388d29fa15bd58c6cf",
    resolveOptions: {},
    factoryMeta: {},
    warnings: [],
    errors: [],
    buildMeta: { providedExports: true },
    buildInfo:
     { cacheable: true,
       fileDependencies: [Set],
       contextDependencies: Set {},
       temporaryProvidedExports: false },
    reasons: [ [ModuleReason] ],
    _chunks:{
       [Chunk],
       _sortFn: [Function: sortById],
       _lastActiveSortFn: null,
       _cache: undefined,
       _cacheOrderIndependent: undefined },
    id: "./src/index.js",
    index: 0,
    index2: 0,
    depth: 0,
    issuer: null,
    profile: undefined,
    prefetched: false,
    built: true,
    used: null,
    usedExports: null,
    optimizationBailout: [],
    _rewriteChunkInReasons: undefined,
    useSourceMap: true,
    _source:{
       _value:
        "module.exports = {
  doubleLine: function doubleLine(arr) {
    if (arr && !Array.isArray(arr)) {
      console.error("the first params type must be Array");
      return;
    }

    return {
      credits: {
        enabled: false // 禁用版权信息

      },
      chart: {
        width: "400",
        height: "400",
        type: "area",
        backgroundColor: {
          linearGradient: [0, 0, 500, 500],
          stops: [[0, "rgba(14, 8, 55,1)"], [1, "rgba(14, 8, 55,1)"]]
        }
      },
      title: {
        text: "",
        style: {
          color: "#a6aed2",
          font: "bold 16px "Trebuchet MS", Verdana, sans-serif"
        }
      },
      xAxis: {
        categories: ["10:00", "10:30", "11:00", "11:30", "12:00", "12:30", "13:00", "13:30", "14:00", "14:30", "15:00", "15:30", "16:00", "16:30", "16:30", "17:00", "17:30", "18:00", "18:30", "19:00"],
        labels: {
          format: "{value} ",
          style: {
            color: "#746f95",
            fontSize: "12px",
            fontFamily: "微软雅黑"
          }
        },
        maxPadding: 0.05,
        showLastLabel: true,
        // tickmarkPlacement:"on",
        tickColor: "#746f95",
        lineWidth: 1,
        lineColor: "#746f95",
        tickLength: 5,
        minRange: 5,
        tickInterval: 1 // 坐标轴刻度间隔为一星期

      },
      yAxis: {
        gridLineWidth: "0px",
        startOnTick: true,
        endOnTick: false,
        maxPadding: 0.35,
        title: {
          text: null
        },
        labels: {
          // format: "{value} m",
          style: {
            color: "#746f95",
            fontSize: "12px",
            fontFamily: "微软雅黑"
          }
        },
        lineWidth: 1,
        lineColor: "#746f95"
      },
      legend: {
        itemStyle: {
          font: "9pt Trebuchet MS, Verdana, sans-serif",
          color: "#a6aed2"
        },
        itemHoverStyle: {
          color: "#fff"
        }
      },
      tooltip: {
        pointFormat: "{series.name}:  {point.y:,.0f}人"
      },
      plotOptions: {
        area: {
          // pointStart: 1920,
          marker: {
            enabled: false,
            symbol: "circle",
            radius: 2,
            states: {
              hover: {
                enabled: true
              }
            }
          }
        }
      },
      series: arr && arr[0] === "pink" ? [{
        // data: [  110, 235, 369, 640,
        //        1005, 1436, 2063, 3057, 4618, 6444, 9822, 15468, 20434, 24126,
        //        27387, 29459, 31056, 31982, 32040, 31233, 29224, 27342, 26662,
        //        26956, 27912, 28999, 28965, 27826, 25579, 25722, 24826, 24605,
        //        24304, 23464, 23708, 24099, 24357, 24237, 24401, 24344, 23586,
        //        22380, 21004, 17287, 14747, 13076, 12555, 12144, 11009, 10950,
        //        10871, 10824, 10577, 10527, 10475, 10421, 10358, 10295, 10104],
        lineColor: "#e88eb3",
        color: {
          linearGradient: {
            x1: 0,
            x2: 0,
            y1: 0,
            y2: 1
          },
          stops: [[0, "rgba(231,142,179,0.8)"], [1, "rgba(135,56,89,0.5)"]]
        },
        fillOpacity: 0.5,
        name: "进",
        marker: {
          enabled: false
        } // threshold: null // 是否显示负数

      }, {
        // data: ,
        lineColor: "#b946ff",
        color: {
          linearGradient: {
            x1: 0,
            x2: 0,
            y1: 0,
            y2: 1
          },
          stops: [[0, "rgba(152,60,210,0.8)"], [1, "rgba(65,25,90,0.35)"]]
        },
        fillOpacity: 0.5,
        name: "出",
        marker: {
          enabled: false
        },
        threshold: null
      }] : [{
        // data: [  110, 235, 369, 640,
        //        1005, 1436, 2063, 3057, 4618, 6444, 9822, 15468, 20434, 24126,
        //        27387, 29459, 31056, 31982, 32040, 31233, 29224, 27342, 26662,
        //        26956, 27912, 28999, 28965, 27826, 25579, 25722, 24826, 24605,
        //        24304, 23464, 23708, 24099, 24357, 24237, 24401, 24344, 23586,
        //        22380, 21004, 17287, 14747, 13076, 12555, 12144, 11009, 10950,
        //        10871, 10824, 10577, 10527, 10475, 10421, 10358, 10295, 10104],
        lineColor: "#b946ff",
        color: {
          linearGradient: {
            x1: 0,
            x2: 0,
            y1: 0,
            y2: 1
          },
          stops: [[0, "rgba(152,60,210,0.8)"], [1, "rgba(65,25,90,0.35)"]]
        },
        fillOpacity: 0.5,
        name: "进",
        marker: {
          enabled: false
        } // threshold: null // 是否显示负数

      }, {
        // data: ,
        lineColor: "#68d5ee",
        color: {
          linearGradient: {
            x1: 0,
            x2: 0,
            y1: 0,
            y2: 1
          },
          stops: [[0, "rgba(104,213,238,0.8)"], [1, "rgba(7,44,96,0.5)"]]
        },
        fillOpacity: 0.5,
        name: "出",
        marker: {
          enabled: false
        },
        threshold: null
      }]
    };
  },
  columns: function columns() {
    return {
      credits: {
        enabled: false
      },
      chart: {
        type: "column",
        backgroundColor: {
          linearGradient: [0, 0, 500, 500],
          stops: [[0, "rgb(14, 8, 55)"], [1, "rgb(14, 8, 55)"]]
        }
      },
      title: {
        text: "月平均降雨量",
        style: {
          color: "#a6aed2",
          font: "bold 16px "Trebuchet MS", Verdana, sans-serif"
        }
      },
      xAxis: {
        gridLineWidth: "0px",
        startOnTick: true,
        endOnTick: false,
        maxPadding: 0.35,
        categories: ["一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月"],
        labels: {
          format: "{value} ",
          style: {
            color: "#746f95",
            fontSize: "12px",
            fontFamily: "微软雅黑"
          }
        },
        crosshair: true,
        lineWidth: 1,
        lineColor: "#746f95",
        tickLength: 5,
        tickColor: "#746f95"
      },
      yAxis: {
        gridLineWidth: "0px",
        startOnTick: true,
        endOnTick: false,
        maxPadding: 0.35,
        min: 0,
        labels: {
          format: "{value} ",
          style: {
            color: "#746f95",
            fontSize: "12px",
            fontFamily: "微软雅黑"
          }
        },
        title: {
          // 平均时长 (min)
          text: "",
          style: {
            color: "#746f95",
            fontSize: "12px",
            fontFamily: "微软雅黑"
          }
        },
        lineWidth: 1,
        lineColor: "#746f95"
      },
      tooltip: {
        // head + 每个 point + footer 拼接成完整的 table
        headerFormat: "{point.key}",
        pointFormat: "" + "",
        footerFormat: "
{series.name}: {point.y}
", shared: true, useHTML: true }, plotOptions: { column: { borderWidth: 0 } }, legend: { itemStyle: { font: "9pt Trebuchet MS, Verdana, sans-serif", color: "#a6aed2" }, itemHoverStyle: { color: "#fff" } }, series: [{ color: "#3453d4", name: ">120s", data: [1, 2, 3, 4, 5, 6, 7] }, { color: "#ff2674", name: "60~120s", data: [3, 4, 3, 1, 3, 2, 2] }, { color: "#66c3e3", // color:"#66c3e3", name: "<60s", data: [7, 4, 3, 4, 2, 6, 8] }] }; } };", _name: "/Users/orion/Desktop/react-beauty-highcharts/node_modules/babel-loader/lib/index.js!/Users/orion/Desktop/react-beauty-highcharts/src/index.js", _sourceMap: [Object], _originalSource: undefined, _innerSourceMap: undefined }, request: "/Users/orion/Desktop/react-beauty-highcharts/node_modules/babel-loader/lib/index.js!/Users/orion/Desktop/react-beauty-highcharts/src/index.js", userRequest: "/Users/orion/Desktop/react-beauty-highcharts/src/index.js", rawRequest: "./src/index.js", binary: false, parser:{ _pluginCompat: [SyncBailHook], hooks: [Object], options: {}, sourceType: "auto", scope: undefined, state: undefined, comments: undefined }, generator: JavascriptGenerator {}, resource: "/Users/orion/Desktop/react-beauty-highcharts/src/index.js", matchResource: undefined, loaders: [ [Object] ], error: null, _buildHash: "488efbd43aa05371d3f44d94c89abd57", buildTimestamp: 1547885885262, _cachedSources: Map {}, lineToLine: false, _lastSuccessfulBuildMeta: { providedExports: true }, _ast: null } ]

我们看到module的长度也是一个,一样有类型,路径,hash
其中
_source的_value下的module.exports,已经是略微压缩版的了,里面还有n

里面值得分析的还有很多,关于怎么压缩,压缩算法是怎么处理的,二次读源码再详解

周六快乐,刚刚抓娃娃机一个都没抓上,哈哈哈哈,但是我抓的激动开心啊

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