Code Validation

/**
 * Base class for code validation plugins
 * @template T - Configuration type for this validator
 */
export declare class Validator<T> {
  constructor(opts: ValidatorOpts);
}

/**
 * Validator plugin configuration (union of two validator types)
 */
type ValidatorOpts = DedicatedThreadValidator | MultiThreadValidator;

/**
 * Validator that processes all assets at once in a dedicated thread
 */
interface DedicatedThreadValidator {
  /** Validate all assets together */
  validateAll(args: {
    assets: Asset[];
    resolveConfigWithPath: ResolveConfigWithPathFn;
    options: PluginOptions;
    logger: PluginLogger;
    tracer: PluginTracer;
  }): Promise<Array<ValidateResult | null>>;
}

/**
 * Validator that processes assets individually across multiple threads
 */
interface MultiThreadValidator {
  /** Get configuration for an asset */
  getConfig?(args: {
    asset: Asset;
    resolveConfig: ResolveConfigFn;
    options: PluginOptions;
    logger: PluginLogger;
    tracer: PluginTracer;
  }): Promise<ConfigResult>;

  /** Validate a single asset */
  validate(args: {
    asset: Asset;
    config: ConfigResult | void;
    options: PluginOptions;
    logger: PluginLogger;
    tracer: PluginTracer;
  }): Promise<ValidateResult | void>;
}

/**
 * Result from validating an asset
 */
interface ValidateResult {
  /** Validation diagnostics (errors, warnings) */
  diagnostics: Array<Diagnostic>;
  
  /** Whether validation passed */
  isValid: boolean;
  
  /** Additional metadata */
  meta?: Record<string, any>;
}

/**
 * Configuration loading result
 */
interface ConfigResult {
  /** Configuration object */
  config: any;
  
  /** Files that were read to load this config */
  files: Array<FilePath>;
}

/**
 * Function to resolve configuration with path information
 */
type ResolveConfigWithPathFn = (
  configNames: Array<string>,
  fromPath: FilePath
) => Promise<ConfigResult | null>;

/**
 * Function to resolve configuration
 */
type ResolveConfigFn = (
  configNames: Array<string>
) => Promise<any>;

import { Validator } from "@parcel/plugin";
import eslint from "eslint";

export default new Validator({
  // Get configuration for validation
  async getConfig({asset, resolveConfig}) {
    // Only validate JavaScript files
    if (!asset.filePath.endsWith('.js')) {
      return null;
    }

    // Load ESLint configuration
    const config = await resolveConfig([
      '.eslintrc.js',
      '.eslintrc.json',
      '.eslintrc'
    ]);

    return { config, files: [] };
  },

  // Validate single asset
  async validate({asset, config, logger}) {
    if (!config) {
      return null; // Skip validation if no config
    }

    const code = await asset.getCode();
    const linter = new eslint.ESLint({
      baseConfig: config.config,
      useEslintrc: false
    });

    try {
      const results = await linter.lintText(code, {
        filePath: asset.filePath
      });

      const diagnostics = [];
      
      for (const result of results) {
        for (const message of result.messages) {
          diagnostics.push({
            level: message.severity === 2 ? 'error' : 'warning',
            message: message.message,
            filePath: asset.filePath,
            start: {
              line: message.line,
              column: message.column
            },
            hints: message.fix ? ['Run ESLint with --fix to auto-correct this issue'] : undefined
          });
        }
      }

      return {
        diagnostics,
        isValid: diagnostics.every(d => d.level !== 'error')
      };

    } catch (error) {
      return {
        diagnostics: [{
          level: 'error',
          message: `ESLint validation failed: ${error.message}`,
          filePath: asset.filePath
        }],
        isValid: false
      };
    }
  }
});

import { Validator } from "@parcel/plugin";
import typescript from "typescript";

export default new Validator({
  // Validate all TypeScript assets together
  async validateAll({assets, resolveConfigWithPath, options, logger}) {
    // Filter TypeScript assets
    const tsAssets = assets.filter(asset => 
      asset.filePath.endsWith('.ts') || asset.filePath.endsWith('.tsx')
    );

    if (tsAssets.length === 0) {
      return [];
    }

    // Load TypeScript configuration
    const configResult = await resolveConfigWithPath([
      'tsconfig.json'
    ], options.projectRoot);

    const tsConfig = configResult?.config || {};

    // Create TypeScript program
    const fileNames = tsAssets.map(asset => asset.filePath);
    const program = typescript.createProgram(fileNames, tsConfig.compilerOptions || {});

    // Get diagnostics
    const diagnostics = typescript.getPreEmitDiagnostics(program);

    // Convert to validation results
    const results = [];
    
    for (const asset of tsAssets) {
      const assetDiagnostics = diagnostics
        .filter(d => d.file?.fileName === asset.filePath)
        .map(d => this.convertTSDiagnostic(d));

      results.push({
        diagnostics: assetDiagnostics,
        isValid: assetDiagnostics.every(d => d.level !== 'error')
      });
    }

    return results;
  },

  convertTSDiagnostic(diagnostic) {
    const message = typescript.flattenDiagnosticMessageText(
      diagnostic.messageText, 
      '\n'
    );

    let start = undefined;
    if (diagnostic.file && diagnostic.start != null) {
      const pos = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
      start = {
        line: pos.line + 1,
        column: pos.character
      };
    }

    return {
      level: diagnostic.category === typescript.DiagnosticCategory.Error ? 'error' : 'warning',
      message,
      filePath: diagnostic.file?.fileName,
      start,
      documentationURL: `https://typescript.tv/errors/#TS${diagnostic.code}`
    };
  }
});

// Only validate specific file types
if (!asset.filePath.match(/\.(js|ts|jsx|tsx)$/)) {
  return null;
}

// Load validation configuration
const config = await resolveConfig([
  '.eslintrc.js',
  '.eslintrc.json',
  'package.json' // Look for eslintConfig key
]);

// Collect errors from multiple sources
const allDiagnostics = [
  ...syntaxErrors,
  ...lintingErrors,
  ...typeErrors
];

return {
  diagnostics: allDiagnostics,
  isValid: allDiagnostics.every(d => d.level !== 'error')
};