Nuxt/packages/nuxt3/src/auto-imports/composables.ts

import { promises as fsp, existsSync } from 'fs'
import { parse as parsePath } from 'pathe'
import { findExports } from 'mlly'
import { camelCase } from 'scule'
import { AutoImport } from '@nuxt/schema'
import { resolveFiles } from '@nuxt/kit'
import { filterInPlace } from './utils'

export async function scanForComposables (dir: string | string[], autoImports: AutoImport[]) {
  const performScan = async (entry: string) => {
    const files = await resolveFiles(entry, [
      '*.{ts,js,mjs,cjs,mts,cts}',
      '*/index.{ts,js,mjs,cjs,mts,cts}'
    ])

    await Promise.all(
      files.map(async (path) => {
        // Remove original entries from the same import (for build watcher)
        filterInPlace(autoImports, i => i.from !== path)

        const code = await fsp.readFile(path, 'utf-8')
        const exports = findExports(code)
        const defaultExport = exports.find(i => i.type === 'default')

        if (defaultExport) {
          let name = parsePath(path).name
          if (name === 'index') {
            name = parsePath(path.split('/').slice(0, -1).join('/')).name
          }
          autoImports.push({ name: 'default', as: camelCase(name), from: path })
        }
        for (const exp of exports) {
          if (exp.type === 'named') {
            for (const name of exp.names) {
              autoImports.push({ name, as: name, from: path })
            }
          } else if (exp.type === 'declaration') {
            autoImports.push({ name: exp.name, as: exp.name, from: path })
          }
        }
      })
    )
  }

  for (const entry of Array.isArray(dir) ? dir : [dir]) {
    if (!existsSync(entry)) { continue }

    await performScan(entry)
  }
}