feat: improved errors when config can not be found (#85)

Co-authored-by: Anthony Fu <[email protected]>

src/cli.ts

@@ -2,6 +2,7 @@ import process from 'node:process'
 import fs from 'node:fs/promises'
 import { existsSync } from 'node:fs'
 import { relative, resolve } from 'node:path'
+
 import open from 'open'
 import { getPort } from 'get-port-please'
 import cac from 'cac'
@@ -11,6 +12,7 @@ import { createHostServer } from './server'
 import { distDir } from './dirs'
 import { readConfig } from './configs'
 import { MARK_CHECK, MARK_INFO } from './constants'
+import { ConfigInspectorError } from './errors'
 
 const cli = cac(
  'eslint-config-inspector',
@@ -33,12 +35,23 @@ cli
 
  const cwd = process.cwd()
  const outDir = resolve(cwd, options.outDir)
- const configs = await readConfig({
- cwd,
- userConfigPath: options.config,
- userBasePath: options.basePath,
- globMatchedFiles: options.files,
- })
+
+ let configs
+ try {
+ configs = await readConfig({
+ cwd,
+ userConfigPath: options.config,
+ userBasePath: options.basePath,
+ globMatchedFiles: options.files,
+ })
+ }
+ catch (error) {
+ if (error instanceof ConfigInspectorError) {
+ error.prettyPrint()
+ process.exit(1)
+ }
+ throw error
+ }
 
  let baseURL = options.base
  if (!baseURL.endsWith('/'))

src/configs.ts

@@ -1,4 +1,4 @@
-import { dirname, relative, resolve } from 'node:path'
+import { basename, dirname, relative, resolve } from 'node:path'
 import process from 'node:process'
 import { ConfigArray } from '@eslint/config-array'
 import { configArrayFindFiles } from '@voxpelli/config-array-find-files'
@@ -8,7 +8,8 @@ import c from 'picocolors'
 import { resolve as resolveModule } from 'mlly'
 import type { FlatConfigItem, MatchedFile, Payload, RuleInfo } from '../shared/types'
 import { isIgnoreOnlyConfig, matchFile } from '../shared/configs'
-import { MARK_CHECK, MARK_INFO, configFilenames } from './constants'
+import { MARK_CHECK, MARK_INFO, configFilenames, legacyConfigFilenames } from './constants'
+import { ConfigPathError, ConfigPathLegacyError } from './errors'
 
 export interface ReadConfigOptions extends ResolveConfigPathOptions {
  /**
@@ -55,24 +56,46 @@ export async function resolveConfigPath(options: ResolveConfigPathOptions) {
  if (userBasePath)
  userBasePath = resolve(cwd, userBasePath)
 
- const configPath = userConfigPath
- ? resolve(cwd, userConfigPath)
- : await findUp(configFilenames, { cwd: userBasePath || cwd })
+ const lookupBasePath = userBasePath || cwd
 
- if (!configPath)
- throw new Error('Cannot find ESLint config file')
+ let configPath = userConfigPath && resolve(cwd, userConfigPath)
+
+ if (!configPath) {
+ configPath = await findUp(configFilenames, { cwd: lookupBasePath })
+ }
+
+ if (!configPath) {
+ const legacyConfigPath = await findUp(legacyConfigFilenames, { cwd: lookupBasePath })
+
+ throw legacyConfigPath
+ ? new ConfigPathLegacyError(
+ `${relative(cwd, dirname(legacyConfigPath))}/`,
+ basename(legacyConfigPath),
+ )
+ : new ConfigPathError(
+ `${relative(cwd, lookupBasePath)}/`,
+ configFilenames,
+ )
+ }
 
  const basePath = userBasePath || (
  userConfigPath
  ? cwd // When user explicit provide config path, use current working directory as root
  : dirname(configPath) // Otherwise, use config file's directory as root
  )
+
  return {
  basePath,
  configPath,
  }
 }
 
+export interface ESLintConfig {
+ configs: FlatConfigItem[]
+ payload: Payload
+ dependencies: string[]
+}
+
 /**
  * Search and read the ESLint config file, processed into inspector payload with module dependencies
  *
@@ -83,13 +106,15 @@ export async function resolveConfigPath(options: ResolveConfigPathOptions) {
  */
 export async function readConfig(
  options: ReadConfigOptions,
-): Promise<{ configs: FlatConfigItem[], payload: Payload, dependencies: string[] }> {
+): Promise<ESLintConfig> {
  const {
  chdir = true,
  globMatchedFiles: globFiles = true,
  } = options
 
- const { basePath, configPath } = await resolveConfigPath(options)
+ const resolvedConfigPath = await resolveConfigPath(options)
+
+ const { basePath, configPath } = resolvedConfigPath
  if (chdir && basePath !== process.cwd())
  process.chdir(basePath)
 

src/constants.ts

@@ -9,5 +9,14 @@ export const configFilenames = [
  'eslint.config.cts',
 ]
 
+export const legacyConfigFilenames = [
+ '.eslintrc.js',
+ '.eslintrc.cjs',
+ '.eslintrc.yaml',
+ '.eslintrc.yml',
+ '.eslintrc.json',
+]
+
 export const MARK_CHECK = c.green('✔')
 export const MARK_INFO = c.blue('ℹ')
+export const MARK_ERROR = c.red('✖')

src/errors.ts

@@ -0,0 +1,49 @@
+import c from 'picocolors'
+import { MARK_ERROR } from './constants'
+
+export class ConfigInspectorError extends Error {
+ prettyPrint() {
+ console.error(MARK_ERROR, this.message)
+ }
+}
+
+export class ConfigPathError extends ConfigInspectorError {
+ override name = 'ConfigPathError' as const
+
+ constructor(
+ public basePath: string,
+ public configFilenames: string[],
+ ) {
+ super('Cannot find ESLint config file')
+ }
+
+ override prettyPrint() {
+ console.error(MARK_ERROR, this.message, c.dim(`
+
+Looked in ${c.underline(this.basePath)} and parent folders for:
+
+ * ${this.configFilenames.join('\n * ')}`,
+ ))
+ }
+}
+
+export class ConfigPathLegacyError extends ConfigInspectorError {
+ override name = 'ConfigPathLegacyError' as const
+
+ constructor(
+ public basePath: string,
+ public configFilename: string,
+ ) {
+ super('Found ESLint legacy config file')
+ }
+
+ override prettyPrint() {
+ console.error(MARK_ERROR, this.message, c.dim(`
+
+Encountered unsupported legacy config ${c.underline(this.configFilename)} in ${c.underline(this.basePath)}
+
+\`@eslint/config-inspector\` only works with the new flat config format:
+https://eslint.org/docs/latest/use/configure/configuration-files-new`,
+ ))
+ }
+}

src/ws.ts

@@ -1,10 +1,13 @@
+import process from 'node:process'
+
 import chokidar from 'chokidar'
 import type { WebSocket } from 'ws'
 import { WebSocketServer } from 'ws'
 import { getPort } from 'get-port-please'
 import type { ReadConfigOptions } from './configs'
 import { readConfig, resolveConfigPath } from './configs'
 import { MARK_CHECK } from './constants'
+import { ConfigInspectorError } from './errors'
 import type { Payload } from '~~/shared/types'
 
 const readErrorWarning = `Failed to load \`eslint.config.js\`.
@@ -27,7 +30,22 @@ export async function createWsServer(options: CreateWsServerOptions) {
  ws.on('close', () => wsClients.delete(ws))
  })
 
- const { basePath } = await resolveConfigPath(options)
+ let resolvedConfigPath: Awaited<ReturnType<typeof resolveConfigPath>>
+ try {
+ resolvedConfigPath = await resolveConfigPath(options)
+ }
+ catch (e) {
+ if (e instanceof ConfigInspectorError) {
+ e.prettyPrint()
+ process.exit(1)
+ }
+ else {
+ throw e
+ }
+ }
+
+ const { basePath } = resolvedConfigPath
+
  const watcher = chokidar.watch([], {
  ignoreInitial: true,
  cwd: basePath,
@@ -61,7 +79,12 @@ export async function createWsServer(options: CreateWsServerOptions) {
  }
  catch (e) {
  console.error(readErrorWarning)
- console.error(e)
+ if (e instanceof ConfigInspectorError) {
+ e.prettyPrint()
+ }
+ else {
+ console.error(e)
+ }
  return {
  message: readErrorWarning,
  error: String(e),