@hono-filebased-route/core/scripts/generate-routes.ts

A core utility for file-based routing in Hono applications.

import { writeFile } from 'fs/promises'
import {
  getExportedHttpMethods,
  getExportedMiddlewareHandler,
  getFiles,
  getRoutePath,
} from '../utils/load-routes-utils'
import path from 'path'
import { Config, METHODS } from '../types'
import { createLogger } from '../utils/logger'

const defaultConfig: Config = {
  dir: './src/routes',
  output: './src/generated-routes.ts',
  write: true,
  verbose: false,
  externals: [],
  typescript: true,
} as const

export async function generateRoutesFile(config?: Partial<Config>) {
  const { dir, output, write, verbose, externals, typescript } = { ...defaultConfig, ...config }
  const logger = createLogger(verbose)
  logger.info(`Generating routes file..., ${dir}, ${output}`)
  const absoluteRoutesDir = path.resolve(dir)
  const files = await getFiles(absoluteRoutesDir, externals)

  const importStatements: string[] = []
  const routeDefinitions: string[] = []

  importStatements.push(`import { Hono } from 'hono';`)

  let counter = 0
  for (const file of files) {
    const routePath = getRoutePath(file, absoluteRoutesDir)
      .replace(/\\/g, '/')
      .replace(/\/index$/, '')
    const relativePath = path
      .relative(path.dirname(output), file)
      .replace(/\.(ts)$/, '')
      .replace(/\\/g, '/')
    const moduleName = `routeModule${counter++}`

    const exportedMethods = getExportedHttpMethods(file)
    const middlewareHandler = getExportedMiddlewareHandler(file)

    if (!exportedMethods.GET && !exportedMethods.POST) continue

    importStatements.push(`import * as ${moduleName} from './${relativePath}';`)

    const tempHonoVar = `honoApp${moduleName}`
    routeDefinitions.push(`  const ${tempHonoVar} = new Hono();`)

    for (const method of METHODS) {
      if (exportedMethods[method]) {
        if (routePath.endsWith('/*')) {
          const len = routePath.replace(/\/\*$/g, '').length + 1
          if (!middlewareHandler[method])
            routeDefinitions.push(
              `  ${tempHonoVar}.${method.toLowerCase()}('/', async (c) => ${moduleName}.${method}(c, c.req.path.substring(${len}).split('/')));`
            )
          else
            routeDefinitions.push(
              `  ${tempHonoVar}.${method.toLowerCase()}('/', ${moduleName}.config${method}, async (c) => ${moduleName}.${method}(c, c.req.path.substring(${len}).split('/')));`
            )
        } else {
          if (!middlewareHandler[method])
            routeDefinitions.push(`  ${tempHonoVar}.${method.toLowerCase()}('/', ${moduleName}.${method});`)
          else
            routeDefinitions.push(
              `  ${tempHonoVar}.${method.toLowerCase()}('/', ${moduleName}.config${method}, ${moduleName}.${method});`
            )
        }
        logger.info(`Generated route: ${method} ${routePath}`)
      }
    }

    routeDefinitions.push(`  mainApp.route('${routePath}', ${tempHonoVar});`)
  }

  const fileContent = `
// THIS FILE IS AUTO-GENERATED BY scripts/generate-routes.ts. DO NOT EDIT.

${importStatements.join('\n')}

/**
 * Registers all generated file-based routes to the main Hono application.
 * @param mainApp The main Hono application instance.
 */
export function registerGeneratedRoutes(mainApp${typescript ? ': Hono' : ''}) {
${routeDefinitions.join('\n')}
}
`

  if (write) {
    await writeFile(output, fileContent.trimStart())
    logger.info(`Generated routes file: ${output} with ${files.length} routes.`)
  }

  return fileContent.trimStart()
}