浅析webpack源码之Compilation.js粗解(九)
栏目: JavaScript · 发布时间: 5年前
内容简介：我们先看一下 compilation是什么？是一个很大的对象
https://www.cnblogs.com/QH-Ji...
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<string, {hash: string, source: Source, chunk: Chunk}>} */
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 = {\n doubleLine: function doubleLine(arr) {\n if (arr && !Array.isArray(arr)) {\n console.error(\'the first params type must be Array\');\n return;\n }\n\n return {\n credits: {\n enabled: false // 禁用版权信息\n\n },\n chart: {\n width: \'400\',\n height: \'400\',\n type: \'area\',\n backgroundColor: {\n linearGradient: [0, 0, 500, 500],\n stops: [[0, \'rgba(14, 8, 55,1)\'], [1, \'rgba(14, 8, 55,1)\']]\n }\n },\n title: {\n text: \'\',\n style: {\n color: \'#a6aed2\',\n font: \'bold 16px "Trebuchet MS", Verdana, sans-serif\'\n }\n },\n xAxis: {\n 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\'],\n labels: {\n format: \'{value} \',\n style: {\n color: \'#746f95\',\n fontSize: \'12px\',\n fontFamily: \'微软雅黑\'\n }\n },\n maxPadding: 0.05,\n showLastLabel: true,\n // tickmarkPlacement:\'on\',\n tickColor: \'#746f95\',\n lineWidth: 1,\n lineColor: \'#746f95\',\n tickLength: 5,\n minRange: 5,\n tickInterval: 1 // 坐标轴刻度间隔为一星期\n\n },\n yAxis: {\n gridLineWidth: \'0px\',\n startOnTick: true,\n endOnTick: false,\n maxPadding: 0.35,\n title: {\n text: null\n },\n labels: {\n // format: \'{value} m\',\n style: {\n color: \'#746f95\',\n fontSize: \'12px\',\n fontFamily: \'微软雅黑\'\n }\n },\n lineWidth: 1,\n lineColor: \'#746f95\'\n },\n legend: {\n itemStyle: {\n font: \'9pt Trebuchet MS, Verdana, sans-serif\',\n color: \'#a6aed2\'\n },\n itemHoverStyle: {\n color: \'#fff\'\n }\n },\n tooltip: {\n pointFormat: \'{series.name}: <b>{point.y:,.0f}</b>人\'\n },\n plotOptions: {\n area: {\n // pointStart: 1920,\n marker: {\n enabled: false,\n symbol: \'circle\',\n radius: 2,\n states: {\n hover: {\n enabled: true\n }\n }\n }\n }\n },\n series: arr && arr[0] === \'pink\' ? [{\n // data: [ 110, 235, 369, 640,\n // 1005, 1436, 2063, 3057, 4618, 6444, 9822, 15468, 20434, 24126,\n // 27387, 29459, 31056, 31982, 32040, 31233, 29224, 27342, 26662,\n // 26956, 27912, 28999, 28965, 27826, 25579, 25722, 24826, 24605,\n // 24304, 23464, 23708, 24099, 24357, 24237, 24401, 24344, 23586,\n // 22380, 21004, 17287, 14747, 13076, 12555, 12144, 11009, 10950,\n // 10871, 10824, 10577, 10527, 10475, 10421, 10358, 10295, 10104],\n lineColor: \'#e88eb3\',\n color: {\n linearGradient: {\n x1: 0,\n x2: 0,\n y1: 0,\n y2: 1\n },\n stops: [[0, \'rgba(231,142,179,0.8)\'], [1, \'rgba(135,56,89,0.5)\']]\n },\n fillOpacity: 0.5,\n name: \'进\',\n marker: {\n enabled: false\n } // threshold: null // 是否显示负数\n\n }, {\n // data: ,\n lineColor: \'#b946ff\',\n color: {\n linearGradient: {\n x1: 0,\n x2: 0,\n y1: 0,\n y2: 1\n },\n stops: [[0, \'rgba(152,60,210,0.8)\'], [1, \'rgba(65,25,90,0.35)\']]\n },\n fillOpacity: 0.5,\n name: \'出\',\n marker: {\n enabled: false\n },\n threshold: null\n }] : [{\n // data: [ 110, 235, 369, 640,\n // 1005, 1436, 2063, 3057, 4618, 6444, 9822, 15468, 20434, 24126,\n // 27387, 29459, 31056, 31982, 32040, 31233, 29224, 27342, 26662,\n // 26956, 27912, 28999, 28965, 27826, 25579, 25722, 24826, 24605,\n // 24304, 23464, 23708, 24099, 24357, 24237, 24401, 24344, 23586,\n // 22380, 21004, 17287, 14747, 13076, 12555, 12144, 11009, 10950,\n // 10871, 10824, 10577, 10527, 10475, 10421, 10358, 10295, 10104],\n lineColor: \'#b946ff\',\n color: {\n linearGradient: {\n x1: 0,\n x2: 0,\n y1: 0,\n y2: 1\n },\n stops: [[0, \'rgba(152,60,210,0.8)\'], [1, \'rgba(65,25,90,0.35)\']]\n },\n fillOpacity: 0.5,\n name: \'进\',\n marker: {\n enabled: false\n } // threshold: null // 是否显示负数\n\n }, {\n // data: ,\n lineColor: \'#68d5ee\',\n color: {\n linearGradient: {\n x1: 0,\n x2: 0,\n y1: 0,\n y2: 1\n },\n stops: [[0, \'rgba(104,213,238,0.8)\'], [1, \'rgba(7,44,96,0.5)\']]\n },\n fillOpacity: 0.5,\n name: \'出\',\n marker: {\n enabled: false\n },\n threshold: null\n }]\n };\n },\n columns: function columns() {\n return {\n credits: {\n enabled: false\n },\n chart: {\n type: \'column\',\n backgroundColor: {\n linearGradient: [0, 0, 500, 500],\n stops: [[0, \'rgb(14, 8, 55)\'], [1, \'rgb(14, 8, 55)\']]\n }\n },\n title: {\n text: \'月平均降雨量\',\n style: {\n color: \'#a6aed2\',\n font: \'bold 16px "Trebuchet MS", Verdana, sans-serif\'\n }\n },\n xAxis: {\n gridLineWidth: \'0px\',\n startOnTick: true,\n endOnTick: false,\n maxPadding: 0.35,\n 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\'],\n labels: {\n format: \'{value} \',\n style: {\n color: \'#746f95\',\n fontSize: \'12px\',\n fontFamily: \'微软雅黑\'\n }\n },\n crosshair: true,\n lineWidth: 1,\n lineColor: \'#746f95\',\n tickLength: 5,\n tickColor: \'#746f95\'\n },\n yAxis: {\n gridLineWidth: \'0px\',\n startOnTick: true,\n endOnTick: false,\n maxPadding: 0.35,\n min: 0,\n labels: {\n format: \'{value} \',\n style: {\n color: \'#746f95\',\n fontSize: \'12px\',\n fontFamily: \'微软雅黑\'\n }\n },\n title: {\n // 平均时长 (min)\n text: \'\',\n style: {\n color: \'#746f95\',\n fontSize: \'12px\',\n fontFamily: \'微软雅黑\'\n }\n },\n lineWidth: 1,\n lineColor: \'#746f95\'\n },\n tooltip: {\n // head + 每个 point + footer 拼接成完整的 table\n headerFormat: \'<span style="font-size:10px">{point.key}</span><table>\',\n pointFormat: \'<tr><td style="color:{series.color};padding:0">{series.name}: </td>\' + \'<td style="padding:0"><b>{point.y} </b></td></tr>\',\n footerFormat: \'</table>\',\n shared: true,\n useHTML: true\n },\n plotOptions: {\n column: {\n borderWidth: 0\n }\n },\n legend: {\n itemStyle: {\n font: \'9pt Trebuchet MS, Verdana, sans-serif\',\n color: \'#a6aed2\'\n },\n itemHoverStyle: {\n color: \'#fff\'\n }\n },\n series: [{\n color: \'#3453d4\',\n name: \'>120s\',\n data: [1, 2, 3, 4, 5, 6, 7]\n }, {\n color: \'#ff2674\',\n name: \'60~120s\',\n data: [3, 4, 3, 1, 3, 2, 2]\n }, {\n color: \'#66c3e3\',\n // color:\'#66c3e3\',\n name: \'<60s\',\n data: [7, 4, 3, 4, 2, 6, 8]\n }]\n };\n }\n};',
_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:smile:
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