Azure Monitor: build monaco with webpack WIP

scripts/webpack/loaders/compile.js

@@ -0,0 +1,87 @@
+const loaderUtils = require('loader-utils');
+
+const WebWorkerTemplatePlugin = require('webpack/lib/webworker/WebWorkerTemplatePlugin');
+const ExternalsPlugin = require('webpack/lib/ExternalsPlugin');
+const NodeTargetPlugin = require('webpack/lib/node/NodeTargetPlugin');
+const LoaderTargetPlugin = require('webpack/lib/LoaderTargetPlugin');
+const SingleEntryPlugin = require('webpack/lib/SingleEntryPlugin');
+
+const COMPILATION_METADATA = Symbol('COMPILATION_METADATA');
+
+module.exports.COMPILATION_METADATA = COMPILATION_METADATA;
+
+module.exports.pitch = function pitch(remainingRequest) {
+  const { target, plugins = [], output, emit } = loaderUtils.getOptions(this) || {};
+
+  if (target !== 'worker') {
+    throw new Error(`Unsupported compile target: ${JSON.stringify(target)}`);
+  }
+
+  this.cacheable(false);
+
+  const { filename, options = {} } = getOutputFilename(output, { target });
+
+  // eslint-disable-next-line no-underscore-dangle
+  const currentCompilation = this._compilation;
+
+  const outputFilename = loaderUtils.interpolateName(this, filename, {
+    context: options.context || currentCompilation.options.context,
+    regExp: options.regExp,
+  });
+
+  const outputOptions = {
+    filename: outputFilename,
+    chunkFilename: `${outputFilename}.[id]`,
+    namedChunkFilename: null,
+  };
+
+  const compilerOptions = currentCompilation.compiler.options;
+  const childCompiler = currentCompilation.createChildCompiler('worker', outputOptions, [
+    // https://github.com/webpack/webpack/blob/master/lib/WebpackOptionsApply.js
+    new WebWorkerTemplatePlugin(outputOptions),
+    new LoaderTargetPlugin('webworker'),
+    ...((this.target === 'web') || (this.target === 'webworker') ? [] : [new NodeTargetPlugin()]),
+
+    // https://github.com/webpack-contrib/worker-loader/issues/95#issuecomment-352856617
+    ...(compilerOptions.externals ? [new ExternalsPlugin(compilerOptions.externals)] : []),
+
+    ...plugins,
+
+    new SingleEntryPlugin(this.context, `!!${remainingRequest}`, 'main'),
+  ]);
+
+  const subCache = `subcache ${__dirname} ${remainingRequest}`;
+
+  childCompiler.plugin('compilation', (compilation) => {
+    if (!compilation.cache) { return; }
+    if (!(subCache in compilation.cache)) { Object.assign(compilation.cache, { [subCache]: {} }); }
+    Object.assign(compilation, { cache: compilation.cache[subCache] });
+  });
+
+  const callback = this.async();
+
+  childCompiler.runAsChild((error, entries, compilation) => {
+    if (error) { return callback(error); }
+    if (entries.length === 0) { return callback(null, null); }
+    const mainFilename = entries[0].files[0];
+    if (emit === false) { delete currentCompilation.assets[mainFilename]; }
+    callback(null, compilation.assets[mainFilename].source(), null, {
+      [COMPILATION_METADATA]: entries[0].files,
+    });
+  });
+};
+
+function getOutputFilename(options, { target }) {
+  if (!options) { return { filename: `[hash].${target}.js`, options: undefined }; }
+  if (typeof options === 'string') { return { filename: options, options: undefined }; }
+  if (typeof options === 'object') {
+    return {
+      filename: options.filename,
+      options: {
+        context: options.context,
+        regExp: options.regExp,
+      },
+    };
+  }
+  throw new Error(`Invalid compile output options: ${options}`);
+}