Improve preview entries

scopes/preview/preview/generate-link.ts

@@ -1,6 +1,12 @@
-import { toWindowsCompatiblePath } from '@teambit/toolbox.path.to-windows-compatible-path';
-import camelcase from 'camelcase';
 import type { ComponentMap } from '@teambit/component';
+import { join } from 'path';
+import { outputFileSync } from 'fs-extra';
+import objectHash from 'object-hash';
+import camelcase from 'camelcase';
+import { toWindowsCompatiblePath } from '@teambit/toolbox.path.to-windows-compatible-path';
+import { getPreviewDistDir } from './mk-temp-dir';
+
+const previewDistDir = getPreviewDistDir();
 
 export type MainModulesMap = {
   /**
@@ -10,56 +16,71 @@ export type MainModulesMap = {
   [envId: string]: string;
 };
 
+type ModuleLink = {
+  envId: string;
+  varName: string;
+  resolveFrom: string;
+};
+
+type ComponentLink = {
+  componentIdentifier: string;
+  modules: {
+    varName: string;
+    resolveFrom: string;
+  }[];
+};
+
 // :TODO refactor to building an AST and generate source code based on it.
 export function generateLink(
   prefix: string,
   componentMap: ComponentMap<string[]>,
   mainModulesMap?: MainModulesMap,
-  isSplitComponentBundle = false
+  isSplitComponentBundle = false,
+  tempPackageDir?: string
 ): string {
-  const links = componentMap.toArray().map(([component, modulePath], compIdx) => ({
+  const componentLinks: ComponentLink[] = componentMap.toArray().map(([component, modulePath], compIdx) => ({
     componentIdentifier: component.id.fullName,
     modules: modulePath.map((path, pathIdx) => ({
       varName: moduleVarName(compIdx, pathIdx),
       resolveFrom: toWindowsCompatiblePath(path),
     })),
   }));
 
-  let modulesLinks;
-  if (mainModulesMap) {
-    modulesLinks = Object.entries(mainModulesMap).map(([envId, path]) => {
-      const resolveFrom = toWindowsCompatiblePath(path);
-      const varName = getEnvVarName(envId);
-      return { envId, varName, resolveFrom };
-    });
-  }
+  const moduleLinks: ModuleLink[] = Object.entries(mainModulesMap || {}).map(([envId, path]) => {
+    const resolveFrom = toWindowsCompatiblePath(path);
+    const varName = getEnvVarName(envId);
+    return { envId, varName, resolveFrom };
+  });
 
-  return `
-import { linkModules } from '@teambit/preview/dist/preview.preview.runtime.js';
+  const contents = `
+import { linkModules } from '${previewDistDir}/preview.preview.runtime.js';
 
-${links
-  .map((link) => link.modules.map((module) => `import * as ${module.varName} from "${module.resolveFrom}";`).join('\n'))
-  .filter((line) => line !== '') // prevent empty lines
-  .join('\n')}
+${getModuleImports(moduleLinks, tempPackageDir)}
 
-${modulesLinks.map((module) => `import * as ${module.varName} from "${module.resolveFrom}";`).join('\n')}
+${getComponentImports(componentLinks)}
 
 linkModules('${prefix}', {
   modulesMap: {
-    ${modulesLinks
+    ${moduleLinks
       // must include all components, including empty
-      .map((module) => `"${module.envId}": ${module.varName}`)
+      .map((moduleLink) => `"${moduleLink.envId}": ${moduleLink.varName}`)
       .join(',\n    ')}
   },
   isSplitComponentBundle: ${isSplitComponentBundle},
   componentMap: {
-${links
+${componentLinks
   // must include all components, including empty
-  .map((link) => `    "${link.componentIdentifier}": [${link.modules.map((module) => module.varName).join(', ')}]`)
+  .map(
+    (componentLink) =>
+      `    "${componentLink.componentIdentifier}": [${componentLink.modules
+        .map((module) => module.varName)
+        .join(', ')}]`
+  )
   .join(',\n')}
   }
 });
 `;
+  return contents;
 }
 
 function moduleVarName(componentIdx: number, fileIdx: number) {
@@ -71,3 +92,23 @@ function getEnvVarName(envId: string) {
   const varName = `${envNameFormatted}MainModule`;
   return varName;
 }
+
+function getModuleImports(moduleLinks: ModuleLink[] = [], tempPackageDir?: string): string {
+  const hash = objectHash(moduleLinks);
+  const tempFileName = `preview-modules-${hash}.mjs`;
+  const tempFilePath = join(tempPackageDir || previewDistDir, tempFileName);
+  const tempFileContents = moduleLinks
+    .map((module) => `export * as ${module.varName} from "${module.resolveFrom}";`)
+    .join('\n');
+  outputFileSync(tempFilePath, tempFileContents);
+  return `import {${moduleLinks.map((moduleLink) => moduleLink.varName).join(', ')}} from "${tempFilePath}";`;
+}
+
+function getComponentImports(componentLinks: ComponentLink[] = []): string {
+  return componentLinks
+    .map((link) =>
+      link.modules.map((module) => `import * as ${module.varName} from "${module.resolveFrom}";`).join('\n')
+    )
+    .filter((line) => line !== '') // prevent empty lines
+    .join('\n');
+}

scopes/preview/preview/mk-temp-dir.ts

@@ -1,7 +1,16 @@
 import { mkdtempSync } from 'fs-extra';
 import { tmpdir } from 'os';
-import { sep } from 'path';
+import { sep, join } from 'path';
+import { getAspectDirFromBvm } from '@teambit/aspect-loader';
 
 export function makeTempDir(prefix = '') {
   return mkdtempSync(`${tmpdir()}${sep}${prefix}`);
 }
+
+export function getPreviewDistDir(): string {
+  try {
+    return join(getAspectDirFromBvm('@teambit/preview'), 'dist');
+  } catch (err) {
+    return __dirname;
+  }
+}

scopes/preview/preview/pre-bundle.ts

@@ -14,6 +14,9 @@ import { promisify } from 'util';
 import { PreviewAspect } from './preview.aspect';
 import { createWebpackConfig } from './webpack/webpack.config';
 import { clearConsole } from './pre-bundle-utils';
+import { getPreviewDistDir } from './mk-temp-dir';
+
+const previewDistDir = getPreviewDistDir();
 
 export const RUNTIME_NAME = 'preview';
 export const PUBLIC_DIR = join('public', 'bit-preview');
@@ -131,7 +134,7 @@ export async function generateBundlePreviewEntry(rootAspectId: string, previewPr
   config['teambit.harmony/bit'] = rootAspectId;
 
   const contents = [imports, `run(${JSON.stringify(config, null, 2)});`].join('\n');
-  const previewRuntime = resolve(join(__dirname, `preview.entry.${sha1(contents)}.js`));
+  const previewRuntime = resolve(join(previewDistDir, `preview.entry.${sha1(contents)}.js`));
 
   if (!existsSync(previewRuntime)) {
     outputFileSync(previewRuntime, contents);

scopes/preview/preview/preview.main.runtime.ts

@@ -20,7 +20,7 @@ import { CACHE_ROOT } from '@teambit/legacy/dist/constants';
 import { BitError } from '@teambit/bit-error';
 import objectHash from 'object-hash';
 import { uniq } from 'lodash';
-import { writeFileSync, existsSync, mkdirSync } from 'fs-extra';
+import { writeFileSync, existsSync, mkdirSync, ensureDirSync, writeJSONSync } from 'fs-extra';
 import { join } from 'path';
 import { PkgAspect, PkgMain } from '@teambit/pkg';
 import { AspectLoaderAspect, getAspectDir, getAspectDirFromBvm } from '@teambit/aspect-loader';
@@ -639,6 +639,17 @@ export class PreviewMain {
   private writeHash = new Map<string, string>();
   private timestamp = Date.now();
 
+  private ensureTempPackage() {
+    const workspacePath = this.workspace?.path;
+    const tempPackageDir = workspacePath ? join(workspacePath, 'node_modules', '@teambit', '_local') : '';
+    if (tempPackageDir) {
+      ensureDirSync(tempPackageDir);
+      writeJSONSync(join(tempPackageDir, 'package.json'), { name: '@teambit/_local' });
+      writeFileSync(join(tempPackageDir, 'index.js'), 'module.exports = {};');
+      return tempPackageDir;
+    }
+  }
+
   /**
    * write a link to load custom modules dynamically.
    * @param prefix write
@@ -653,7 +664,8 @@ export class PreviewMain {
     dirName: string,
     isSplitComponentBundle: boolean
   ) {
-    const contents = generateLink(prefix, moduleMap, mainModulesMap, isSplitComponentBundle);
+    const tempPackageDir = this.ensureTempPackage();
+    const contents = generateLink(prefix, moduleMap, mainModulesMap, isSplitComponentBundle, tempPackageDir);
     return this.writeLinkContents(contents, dirName, prefix);
   }