fix: improve error handling

Author: bpbuch

messages/lightning.dev.component.md

@@ -28,6 +28,14 @@ Unable to find components
 
 Unable to determine component name
 
+# error.component-metadata
+
+Failed to parse component metadata at: %s
+
+# error.component-not-found
+
+Unable to find component with name: %s
+
 # examples
 
 - Select a component and launch the component preview:

src/commands/lightning/dev/component.ts

@@ -32,44 +32,57 @@ export default class LightningDevComponent extends SfCommand<void> {
   };
 
   public async run(): Promise<void> {
-    const project = await SfProject.resolve();
     const { flags } = await this.parse(LightningDevComponent);
+    const project = await SfProject.resolve();
 
-    let name = flags.name;
-    if (!name) {
-      const dirs = await ComponentUtils.getComponentPaths(project);
-      if (!dirs) {
-        throw new Error(messages.getMessage('error.directory'));
-      }
+    const namespacePaths = await ComponentUtils.getNamespacePaths(project);
+    const componentPaths = await ComponentUtils.getAllComponentPaths(namespacePaths);
+    if (!componentPaths) {
+      throw new Error(messages.getMessage('error.directory'));
+    }
 
-      const components = (
-        await Promise.all(
-          dirs.map(async (dir) => {
-            const xml = await ComponentUtils.getComponentMetadata(dir);
-            if (!xml) {
-              return undefined;
-            }
+    const components = (
+      await Promise.all(
+        componentPaths.map(async (componentPath) => {
+          let xml;
 
-            const componentName = path.basename(dir);
-            const label = ComponentUtils.componentNameToTitleCase(componentName);
+          try {
+            xml = await ComponentUtils.getComponentMetadata(componentPath);
+          } catch (err) {
+            this.warn(messages.getMessage('error.component-metadata', [componentPath]));
+          }
 
-            return {
-              name: componentName,
-              label: xml.LightningComponentBundle.masterLabel ?? label,
-              description: xml.LightningComponentBundle.description ?? '',
-            };
-          })
-        )
-      ).filter((component) => !!component);
+          // components must have meta xml to be previewed
+          if (!xml) {
+            return undefined;
+          }
 
+          const componentName = path.basename(componentPath);
+          const label = ComponentUtils.componentNameToTitleCase(componentName);
+
+          return {
+            name: componentName,
+            label: xml.LightningComponentBundle.masterLabel ?? label,
+            description: xml.LightningComponentBundle.description ?? '',
+          };
+        })
+      )
+    ).filter((component) => !!component);
+
+    let name = flags.name;
+    if (name) {
+      // validate that the component exists before launching the server
+      if (!components.find((component) => name === component.name)) {
+        throw new Error(messages.getMessage('error.component-not-found', [name]));
+      }
+    } else {
+      // prompt the user for a name if one was not provided
       name = await PromptUtils.promptUserToSelectComponent(components);
       if (!name) {
         throw new Error(messages.getMessage('error.component'));
       }
     }
 
-    this.log('Starting application on port 3000...');
-
     const port = parseInt(process.env.PORT ?? '3000', 10);
 
     await cmpDev({

src/shared/componentUtils.ts

@@ -6,9 +6,9 @@
  */
 import path from 'node:path';
 import fs from 'node:fs';
-import { SfProject } from '@salesforce/core';
 import { glob } from 'glob';
 import { parseStringPromise } from 'xml2js';
+import { SfProject } from '@salesforce/core';
 
 export type LwcMetadata = {
   LightningComponentBundle: {
@@ -26,33 +26,32 @@ export class ComponentUtils {
     return componentName.replace(/([A-Z])/g, ' $1').replace(/^./, (str) => str.toUpperCase());
   }
 
-  public static async getComponentPaths(project: SfProject): Promise<string[]> {
+  public static async getNamespacePaths(project: SfProject): Promise<string[]> {
     const packageDirs = project.getPackageDirectories();
-    const namespacePaths = (
-      await Promise.all(packageDirs.map((dir) => glob(`${dir.fullPath}/**/lwc`, { absolute: true })))
-    ).flat();
 
-    return (
-      await Promise.all(
-        namespacePaths.map(async (namespacePath): Promise<string[]> => {
-          const children = await fs.promises.readdir(namespacePath, { withFileTypes: true });
+    return (await Promise.all(packageDirs.map((dir) => glob(`${dir.fullPath}/**/lwc`, { absolute: true })))).flat();
+  }
 
-          return children
-            .filter((child) => child.isDirectory())
-            .map((child) => path.join(child.parentPath, child.name));
-        })
-      )
+  public static async getAllComponentPaths(namespacePaths: string[]): Promise<string[]> {
+    return (
+      await Promise.all(namespacePaths.map((namespacePath) => ComponentUtils.getComponentPaths(namespacePath)))
     ).flat();
   }
 
+  public static async getComponentPaths(namespacePath: string): Promise<string[]> {
+    const children = await fs.promises.readdir(namespacePath, { withFileTypes: true });
+
+    return children.filter((child) => child.isDirectory()).map((child) => path.join(child.parentPath, child.name));
+  }
+
   public static async getComponentMetadata(dirname: string): Promise<LwcMetadata | undefined> {
     const componentName = path.basename(dirname);
     const metaXmlPath = path.join(dirname, `${componentName}.js-meta.xml`);
     if (!fs.existsSync(metaXmlPath)) {
       return undefined;
     }
 
-    const xmlContent = fs.readFileSync(metaXmlPath, 'utf8');
+    const xmlContent = await fs.promises.readFile(metaXmlPath, 'utf8');
     const parsedData = (await parseStringPromise(xmlContent)) as LwcMetadata;
     if (!this.isLwcMetadata(parsedData)) {
       return undefined;