packages/cli: make src-relative imports work

packages/cli/bin/backstage-cli

@@ -5,12 +5,60 @@ const path = require('path');
 // Figure out whether we're running inside the backstage repo or as an installed dependency
 const isLocal = require('fs').existsSync(path.resolve(__dirname, '../src'));
 if (!isLocal) {
+  // src-relative imports are a pain to get to work with plain tsc compilation, as the
+  // transpiled code will maintain the imports as they are in the source. Which means an
+  // import for `helpers/paths` will start like that in the output, which won't work in NodeJS.
+  //
+  // This is a solution for getting src-relative imports to work with typescript/node in
+  // the published package. We're using `module: "amd"` to ship the entire cli implementation
+  // in one file, and it also happens to generate correct module definition and import statements.
+
+  // Minimal AMD implementation
+  const moduleFactories = {};
+  const moduleCache = {};
+  global.define = (name, deps, moduleFunc) => {
+    moduleFactories[name] = () => {
+      const exportsObj = {};
+      const impls = deps.slice(2).map(dep => {
+        const factory = moduleFactories[dep];
+        if (!factory) {
+          return require(dep);
+        }
+        if (!moduleCache[dep]) {
+          moduleCache[dep] = factory();
+        }
+        return moduleCache[dep];
+      });
+
+      moduleFunc(require, exportsObj, ...impls);
+
+      return exportsObj;
+    };
+  };
   require('../dist');
+
+  // index module is the entrypoint
+  moduleFactories.index();
 } else {
+  const tsConfigPath = path.resolve(__dirname, '../tsconfig.json');
+  const {
+    baseUrl: relativeBaseUrl,
+    paths = {},
+  } = require(tsConfigPath).compilerOptions;
+  const baseUrl = path.resolve(__dirname, '..', relativeBaseUrl);
+
+  // Use tsconfig-paths to resolve src-relative paths during development
+  const cleanupPaths = require('tsconfig-paths').register({ baseUrl, paths });
+
   require('ts-node').register({
     project: path.resolve(__dirname, '../tsconfig.json'),
+    compilerOptions: {
+      module: 'CommonJS',
+    },
     transpileOnly: true,
   });
 
   require('../src');
+
+  cleanupPaths();
 }