.25-淺析webpack源碼之事件流compilation(3)

　　這一節跑下一批plugin。

compiler.apply(
    new EnsureChunkConditionsPlugin(),
    new RemoveParentModulesPlugin(),
    new RemoveEmptyChunksPlugin(),
    new MergeDuplicateChunksPlugin(),
    new FlagIncludedChunksPlugin(),
    new OccurrenceOrderPlugin(true),
    new FlagDependencyExportsPlugin(),
    new FlagDependencyUsagePlugin()
);

　　希望不要跟上一節一樣，全是plugin。

　　流程如圖(看看流程圖就行了，後面也沒有什麼內容)：

EnsureChunkConditionsPlugin

class EnsureChunkConditionsPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            const triesMap = new Map();
            compilation.plugin(["optimize-chunks-basic", "optimize-extracted-chunks-basic"], (chunks) => { /**/ });
        });
    }
}

　　這個看看就懂，不解釋了。

RemoveParentModulesPlugin

class RemoveParentModulesPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin(["optimize-chunks-basic", "optimize-extracted-chunks-basic"], (chunks) => { /**/ });
        });
    }
}

　　難道又是另一批plugin麽……

RemoveEmptyChunksPlugin

class RemoveEmptyChunksPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin(["optimize-chunks-basic", "optimize-extracted-chunks-basic"], (chunks) => { /**/ });
        });
    }
}

　　是的。

MergeDuplicateChunksPlugin

class MergeDuplicateChunksPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin("optimize-chunks-basic", (chunks) => { /**/ });
        });
    }
}

FlagIncludedChunksPlugin

class FlagIncludedChunksPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin("optimize-chunk-ids", (chunks) => { /**/ });
        });
    }
}

OccurrenceOrderPlugin

class OccurrenceOrderPlugin {
    // true
    constructor(preferEntry) {
        if (preferEntry !== undefined && typeof preferEntry !== "boolean") {
            throw new Error("Argument should be a boolean.\nFor more info on this plugin, see https://webpack.js.org/plugins/");
        }
        this.preferEntry = preferEntry;
    }
    apply(compiler) {
        const preferEntry = this.preferEntry;
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin("optimize-module-order", (modules) => { /**/ });
            compilation.plugin("optimize-chunk-order", (chunks) => { /**/ });
        });
    }
}

　　看到那個錯誤提示就想笑，這個插件除了你自己誰會去調用啊。

FlagDependencyExportsPlugin

class FlagDependencyExportsPlugin {
    apply(compiler) {
        compiler.plugin("compilation", (compilation) => {
            compilation.plugin("finish-modules", (modules) => { /**/ });

            function addToSet(a, b) { /**/ }
        });
    }
}

FlagDependencyUsagePlugin

class FlagDependencyUsagePlugin {
    apply(compiler) {
        compiler.plugin("compilation", compilation => {
            compilation.plugin("optimize-modules-advanced", modules => { /**/ });

            function addToSet(a, b) { /**/ }

            function isSubset(biggerSet, subset) { /**/ }
        });
    }
}

　　總的來說，這一批plugin是針對模塊的，不過仍然沒有任何實際行為。

　　還剩下3個也一併過了吧。

TemplatedPathPlugin

class TemplatedPathPlugin {
    apply(compiler) {
        compiler.plugin("compilation", compilation => {
            const mainTemplate = compilation.mainTemplate;
            mainTemplate.plugin("asset-path", replacePathVariables);
            mainTemplate.plugin("global-hash", function(chunk, paths) { /**/ });
            mainTemplate.plugin("hash-for-chunk", function(hash, chunk) { /**/ });
        });
    }
}

RecordIdsPlugin

class RecordIdsPlugin {
    apply(compiler) {
        compiler.plugin("compilation", compilation => {
            compilation.plugin("record-modules", (modules, records) => { /**/ });
            compilation.plugin("revive-modules", (modules, records) => { /**/ });

            function getDepBlockIdent(chunk, block) { /**/ }
            compilation.plugin("record-chunks", (chunks, records) => { /**/ });
            compilation.plugin("revive-chunks", (chunks, records) => { /**/ });
        });
    }
}

WarnCaseSensitiveModulesPlugin

class WarnCaseSensitiveModulesPlugin {
    apply(compiler) {
        compiler.plugin("compilation", compilation => {
            compilation.plugin("seal", () => { /**/ });
        });
    }
}

　　這裡把所有compilation事件流觸發完後，也只是針對不同的階段再次進行plugin，所以詳細過程還需要繼續跑流程。