热重载会破坏应用程序。最终加载程序未返回缓冲区或字符串

Question

我有一个自定义加载器，可以加载以下文件data.js

  const data = {
    a: ()=> 8885555,
    b: ()=> 55555
  }
  module.exports = name => {
    return data[name] && data[name]()
  }

当我更改上述文件时，例如更改b值时，应用程序会中断

ERROR in ../data.js?name=a
Module build failed: Error: Final loader (../data-loader.js) didn't return a Buffer or String
    at runLoaders (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_moduleswebpacklibNormalModule.js:319:18)
    at C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:373:3
    at iterateNormalLoaders (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:214:10)
    at iterateNormalLoaders (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:221:10)
    at C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:236:3
    at runSyncOrAsync (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:124:12)
    at iterateNormalLoaders (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:232:2)
    at Array.<anonymous> (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesloader-runnerlibLoaderRunner.js:205:4)
    at Storage.finished (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesenhanced-resolvelibCachedInputFileSystem.js:43:16)
    at provider (C:Users10Saber.jswebpack-hmr-3-waysmiddlewarenode_modulesenhanced-resolvelibCachedInputFileSystem.js:79:9)
 @ ./index.js 1:10-40
 @ multi webpack-hot-middleware/client?path=/__webpack_hmr&timeout=20000 ./index.js

这是自定义的 webpack 加载器

const devalue = require('devalue')
const vm = require('vm');
module.exports = async function(source, map) {
    const callback = this.async()
    this.addDependency(this.resourcePath);
    const sandbox = {
        require,
        module
    }
    vm.createContext(sandbox);
    const mod = vm.runInContext(source, sandbox)
    const result = await mod(this.resourceQuery.replace('?name=', ''))
    return callback(null, `export default ${devalue(result)}`, map);
}

这是一个复制存储库

Answer 1

所以这是应该做的

const devalue = require('devalue')
const vm = require('vm');
module.exports = async function(source, map) {
    const callback = this.async()
    this.addDependency(this.resourcePath);
    const sandbox = {
        require,
        module: {exports: {}}
    }
    vm.createContext(sandbox);
    const mod = vm.runInContext(source, sandbox)
    const result = await mod(this.resourceQuery.replace('?name=', ''))
    return callback(null, `export default ${devalue(result)}`, map);
}

问题是我用data.js文件module.exports覆盖了加载器module.exports，因为我将相同的module传递给sandbox所以当热重载时，加载器中导出的函数将被替换为不返回字符串的data.js函数(在这种情况下，因为data[name]会undefined(，这就是错误的原因