DEV: Use esbuild to make DiscourseJsProcessor (#23223)

Reverts e2705df and re-lands #23187 and #23219.

The issue was incorrect order of execution of Rails' `assets:precompile` task in our own precompilation stack.

Co-authored-by: David Taylor <david@taylorhq.com>

app/assets/javascripts/js-processor.js

@@ -0,0 +1,157 @@
+// This is executed in mini_racer to provide the JS logic for lib/discourse_js_processor.rb
+
+/* global rails */
+
+const CONSOLE_PREFIX = "[DiscourseJsProcessor] ";
+globalThis.window = {};
+globalThis.console = {
+  log(...args) {
+    rails.logger.info(CONSOLE_PREFIX + args.join(" "));
+  },
+  warn(...args) {
+    rails.logger.warn(CONSOLE_PREFIX + args.join(" "));
+  },
+  error(...args) {
+    rails.logger.error(CONSOLE_PREFIX + args.join(" "));
+  },
+};
+
+import HTMLBarsInlinePrecompile from "babel-plugin-ember-template-compilation";
+import colocatedBabelPlugin from "ember-cli-htmlbars/lib/colocated-babel-plugin";
+import { precompile } from "ember-source/dist/ember-template-compiler";
+import Handlebars from "handlebars";
+import { transform as babelTransform } from "@babel/standalone";
+import { minify as terserMinify } from "terser";
+import RawHandlebars from "discourse-common/addon/lib/raw-handlebars";
+import { WidgetHbsCompiler } from "discourse-widget-hbs/lib/widget-hbs-compiler";
+
+function manipulateAstNodeForTheme(node, themeId) {
+  // Magically add theme id as the first param for each of these helpers)
+  if (
+    node.path.parts &&
+    ["theme-i18n", "theme-prefix", "theme-setting"].includes(node.path.parts[0])
+  ) {
+    if (node.params.length === 1) {
+      node.params.unshift({
+        type: "NumberLiteral",
+        value: themeId,
+        original: themeId,
+        loc: { start: {}, end: {} },
+      });
+    }
+  }
+}
+
+function buildEmberTemplateManipulatorPlugin(themeId) {
+  return function () {
+    return {
+      name: "theme-template-manipulator",
+      visitor: {
+        SubExpression: (node) => manipulateAstNodeForTheme(node, themeId),
+        MustacheStatement: (node) => manipulateAstNodeForTheme(node, themeId),
+      },
+    };
+  };
+}
+
+function buildTemplateCompilerBabelPlugins({ themeId }) {
+  const compiler = { precompile };
+
+  if (themeId) {
+    compiler.precompile = (src, opts) => {
+      return precompile(src, {
+        ...opts,
+        plugins: {
+          ast: [buildEmberTemplateManipulatorPlugin(themeId)],
+        },
+      });
+    };
+  }
+
+  return [
+    colocatedBabelPlugin,
+    WidgetHbsCompiler,
+    [
+      HTMLBarsInlinePrecompile,
+      {
+        compiler,
+        enableLegacyModules: ["ember-cli-htmlbars"],
+      },
+    ],
+  ];
+}
+
+function buildThemeRawHbsTemplateManipulatorPlugin(themeId) {
+  return function (ast) {
+    ["SubExpression", "MustacheStatement"].forEach((pass) => {
+      const visitor = new Handlebars.Visitor();
+      visitor.mutating = true;
+      visitor[pass] = (node) => manipulateAstNodeForTheme(node, themeId);
+      visitor.accept(ast);
+    });
+  };
+}
+
+globalThis.compileRawTemplate = function (source, themeId) {
+  try {
+    const plugins = [];
+    if (themeId) {
+      plugins.push(buildThemeRawHbsTemplateManipulatorPlugin(themeId));
+    }
+    return RawHandlebars.precompile(source, false, { plugins }).toString();
+  } catch (error) {
+    // Workaround for https://github.com/rubyjs/mini_racer/issues/262
+    error.message = JSON.stringify(error.message);
+    throw error;
+  }
+};
+
+globalThis.transpile = function (source, options = {}) {
+  const { moduleId, filename, skipModule, themeId, commonPlugins } = options;
+  const plugins = [];
+
+  plugins.push(...buildTemplateCompilerBabelPlugins({ themeId }));
+  if (moduleId && !skipModule) {
+    plugins.push(["transform-modules-amd", { noInterop: true }]);
+  }
+  plugins.push(...commonPlugins);
+
+  try {
+    return babelTransform(source, {
+      moduleId,
+      filename,
+      ast: false,
+      plugins,
+    }).code;
+  } catch (error) {
+    // Workaround for https://github.com/rubyjs/mini_racer/issues/262
+    error.message = JSON.stringify(error.message);
+    throw error;
+  }
+};
+
+// mini_racer doesn't have native support for getting the result of an async operation.
+// To work around that, we provide a getMinifyResult which can be used to fetch the result
+// in a followup method call.
+let lastMinifyError, lastMinifyResult;
+
+globalThis.minify = async function (sources, options) {
+  lastMinifyError = lastMinifyResult = null;
+  try {
+    lastMinifyResult = await terserMinify(sources, options);
+  } catch (e) {
+    lastMinifyError = e;
+  }
+};
+
+globalThis.getMinifyResult = function () {
+  const error = lastMinifyError;
+  const result = lastMinifyResult;
+
+  lastMinifyError = lastMinifyResult = null;
+
+  if (error) {
+    throw error;
+  }
+  return result;
+};