add impl and test

Author: jonaslagoni

src/utils/gitignore.ts

@@ -0,0 +1,157 @@
+import {readFile, appendFile, writeFile, access} from 'node:fs/promises';
+import path from 'path';
+
+export interface GitignoreUpdateOptions {
+  /**
+   * The base directory where .gitignore is located (defaults to process.cwd())
+   */
+  baseDirectory?: string;
+  /**
+   * Custom comment header to add before the gitignore entries
+   */
+  commentHeader?: string;
+}
+
+export interface GitignoreUpdateResult {
+  /**
+   * Whether the operation was successful
+   */
+  success: boolean;
+  /**
+   * The action that was performed
+   */
+  action: 'created' | 'updated' | 'skipped' | 'error';
+  /**
+   * A message describing what happened
+   */
+  message: string;
+  /**
+   * The paths that were added (if any)
+   */
+  addedPaths?: string[];
+  /**
+   * Error details if the operation failed
+   */
+  error?: string;
+}
+
+/**
+ * Updates or creates a .gitignore file with the specified output paths
+ *
+ * @param outputPaths - Array of paths to add to .gitignore
+ * @param options - Optional configuration for the gitignore update
+ * @returns Result object with operation details
+ *
+ * @example
+ * ```typescript
+ * const result = await updateGitignore(['src/__gen__/payloads', 'src/__gen__/channels']);
+ * if (result.success) {
+ *   console.log(result.message);
+ * }
+ * ```
+ */
+export async function updateGitignore(
+  outputPaths: string[],
+  options: GitignoreUpdateOptions = {}
+): Promise<GitignoreUpdateResult> {
+  // eslint-disable-next-line no-undef
+  const baseDirectory = options.baseDirectory || process.cwd();
+  const commentHeader =
+    options.commentHeader || '# The Codegen Project - generated files';
+  const gitignorePath = path.join(baseDirectory, '.gitignore');
+
+  try {
+    // Check if .gitignore exists
+    await access(gitignorePath);
+
+    // Read existing content
+    const existingContent = await readFile(gitignorePath, 'utf-8');
+
+    // Filter out paths that already exist in .gitignore
+    const newPaths = outputPaths.filter(
+      (outputPath) => !existingContent.includes(outputPath)
+    );
+
+    if (newPaths.length === 0) {
+      return {
+        success: true,
+        action: 'skipped',
+        message:
+          'All output directories already present in .gitignore, skipping',
+        addedPaths: []
+      };
+    }
+
+    // Ensure file ends with newline before adding new entries
+    const separator = existingContent.endsWith('\n') ? '' : '\n';
+    const gitignoreEntry = `${separator}\n${commentHeader}\n${newPaths.join('\n')}\n`;
+
+    await appendFile(gitignorePath, gitignoreEntry);
+
+    return {
+      success: true,
+      action: 'updated',
+      message: `Added ${newPaths.length} output director${newPaths.length === 1 ? 'y' : 'ies'} to .gitignore`,
+      addedPaths: newPaths
+    };
+  } catch (error: any) {
+    if (error.code === 'ENOENT') {
+      // .gitignore doesn't exist, try to create it
+      try {
+        const gitignoreContent = `${commentHeader}\n${outputPaths.join('\n')}\n`;
+        await writeFile(gitignorePath, gitignoreContent);
+
+        return {
+          success: true,
+          action: 'created',
+          message: 'Created .gitignore with generated output directories',
+          addedPaths: outputPaths
+        };
+      } catch (writeError: any) {
+        // Failed to create .gitignore (e.g., directory doesn't exist)
+        return {
+          success: false,
+          action: 'error',
+          message: `Could not create .gitignore: ${writeError.message}`,
+          error: writeError.message
+        };
+      }
+    }
+
+    return {
+      success: false,
+      action: 'error',
+      message: `Could not update .gitignore: ${error.message}`,
+      error: error.message
+    };
+  }
+}
+
+/**
+ * Collects output paths from generator flags
+ *
+ * @param generatorConfigs - Map of generator names to their configurations
+ * @returns Array of output paths
+ *
+ * @example
+ * ```typescript
+ * const paths = collectOutputPaths({
+ *   payloads: { outputPath: 'src/__gen__/payloads' },
+ *   channels: { outputPath: 'src/__gen__/channels' }
+ * });
+ * // Returns: ['src/__gen__/payloads', 'src/__gen__/channels']
+ * ```
+ */
+export function collectOutputPaths(
+  generatorConfigs: Record<string, {outputPath: string} | undefined>
+): string[] {
+  const outputPaths: string[] = [];
+
+  for (const config of Object.values(generatorConfigs)) {
+    if (config?.outputPath) {
+      outputPaths.push(config.outputPath);
+    }
+  }
+
+  return outputPaths;
+}