_compilation property deprecated and undefined in latest webpack ?

[AlexandreBonaventure]

Hi,
with webpack@4.14.0, I'm unable to get this loader working. It throws an error at build time!
I can see _compilation in the deprecated properties in the loader API https://webpack.js.org/api/loaders/#deprecated-context-properties
Maybe it has been removed completely in the latest webpack versions ??

Cannot read property 'createChildCompiler' of undefined
    at Object.loader.pitch (/node_modules/workerize-loader/dist/index.js:28:41)

Here's what gives when I console.log(this._compilation)

{ version: 2,
  resolve: [Function: resolve],
  emitWarning: [Function: emitWarning],
  emitError: [Function: emitError],
  exec: [Function: exec],
  options:
   { context: '' },
  webpack: true,
  'thread-loader': true,
  sourceMap: true,
  context: '/src/core/shared/timer',
  loaderIndex: 1,
  loaders:
   [ { path: '/node_modules/babel-loader/lib/index.js',
       query: '',
       options: undefined,
       ident: undefined,
       normal: [Function],
       pitch: undefined,
       raw: undefined,
       data: null,
       pitchExecuted: true,
       normalExecuted: false,
       request: [Getter/Setter] },
     { path: '/node_modules/worker-loader/dist/cjs.js',
       query: '',
       options: undefined,
       ident: undefined,
       normal: [Function],
       pitch: [Function: pitch],
       raw: undefined,
       data: {},
       pitchExecuted: true,
       normalExecuted: false,
       request: [Getter/Setter] },
     { path: '/node_modules/eslint-loader/index.js',
       query: '??ref--13-0',
       options: [Object],
       ident: 'ref--13-0',
       normal: null,
       pitch: null,
       raw: null,
       data: null,
       pitchExecuted: false,
       normalExecuted: false,
       request: [Getter/Setter] } ],
  resourcePath: '/src/core/shared/timer/refresh.worker.js',
  resourceQuery: '',
  async: [Function: async],
  callback: [Function],
  cacheable: [Function: cacheable],
  addDependency: [Function: addDependency],
  dependency: [Function: addDependency],
  addContextDependency: [Function: addContextDependency],
  getDependencies: [Function: getDependencies],
  getContextDependencies: [Function: getContextDependencies],
  clearDependencies: [Function: clearDependencies],
  resource: [Getter/Setter],
  request: [Getter],
  remainingRequest: [Getter],
  currentRequest: [Getter],
  previousRequest: [Getter],
  query: [Getter],
  data: [Getter] }
{ version: 2,
  resolve: [Function: resolve],
  emitWarning: [Function: emitWarning],
  emitError: [Function: emitError],
  exec: [Function: exec],
  options:
   { context: '' },
  webpack: true,
  'thread-loader': true,
  sourceMap: true,
  context: '/src/location',
  loaderIndex: 1,
  loaders:
   [ { path: '/node_modules/babel-loader/lib/index.js',
       query: '',
       options: undefined,
       ident: undefined,
       normal: [Function],
       pitch: undefined,
       raw: undefined,
       data: null,
       pitchExecuted: true,
       normalExecuted: false,
       request: [Getter/Setter] },
     { path: '/node_modules/worker-loader/dist/cjs.js',
       query: '',
       options: undefined,
       ident: undefined,
       normal: [Function],
       pitch: [Function: pitch],
       raw: undefined,
       data: {},
       pitchExecuted: true,
       normalExecuted: false,
       request: [Getter/Setter] },
     { path: '/node_modules/eslint-loader/index.js',
       query: '??ref--13-0',
       options: [Object],
       ident: 'ref--13-0',
       normal: null,
       pitch: null,
       raw: null,
       data: null,
       pitchExecuted: false,
       normalExecuted: false,
       request: [Getter/Setter] } ],
  resourcePath: '/src/location/conflict-detector.worker.js',
  resourceQuery: '',
  async: [Function: async],
  callback: [Function],
  cacheable: [Function: cacheable],
  addDependency: [Function: addDependency],
  dependency: [Function: addDependency],
  addContextDependency: [Function: addContextDependency],
  getDependencies: [Function: getDependencies],
  getContextDependencies: [Function: getContextDependencies],
  clearDependencies: [Function: clearDependencies],
  resource: [Getter/Setter],
  request: [Getter],
  remainingRequest: [Getter],
  currentRequest: [Getter],
  previousRequest: [Getter],
  query: [Getter],
  data: [Getter] }

Hope to hear from you guys!
Thanks for this awesome package!

[AlexandreBonaventure]

Turns out it was an issue caused by thread-loader used by vue-cli internally not giving the usual loader context. see webpack-contrib/thread-loader#27
However, since _compilation is deprecated, it would be worth to move to the webpack 4 way of using the loader API

[Jmingzi]

Suggest adding exclude to thread loader for specific files