Convert package to ESM

Migration Guide:

This relases changes the package from a Common JS module to an EcmaScript module, and drops support for older versions of Node.

- The minimum version of Node.js supported is now: `12.20.0`, `14.13.1`, and `16.0.0`
- The package must now be imported using the native `import` syntax instead of with `require`

.travis.yml

@@ -1,9 +1,8 @@
 language: node_js
 node_js:
-  - '13'
-  - '12'
-  - '10'
-  - '10.13.0'
+  - '16.0.0'
+  - '14.13.1'
+  - '12.20.0'
 os:
   - linux
   - osx

README.md

@@ -18,8 +18,8 @@ Multer adds a `body` object and a `file` or `files` object to the `request` obje
 Basic usage example:
 
 ```javascript
-const multer = require('multer')
-const express = require('express')
+import multer from 'multer'
+import express from 'express'
 
 const app = express()
 const upload = multer()
@@ -49,8 +49,8 @@ app.post('/cool-profile', cpUpload, (req, res, next) => {
 In case you need to handle a text-only multipart form, you can use the `.none()` method, example:
 
 ```javascript
-const multer = require('multer')
-const express = require('express')
+import multer from 'multer'
+import express from 'express'
 
 const app = express()
 const upload = multer()

index.js

@@ -1,7 +1,7 @@
-const createFileFilter = require('./lib/file-filter')
-const createMiddleware = require('./lib/middleware')
+import bytes from 'bytes'
 
-const bytes = require('bytes')
+import createFileFilter from './lib/file-filter.js'
+import createMiddleware from './lib/middleware.js'
 
 const kLimits = Symbol('limits')
 
@@ -60,7 +60,7 @@ class Multer {
   }
 }
 
-function multer (options = {}) {
+export default function multer (options = {}) {
   if (options === null) throw new TypeError('Expected object for argument "options", got null')
   if (typeof options !== 'object') throw new TypeError(`Expected object for argument "options", got ${typeof options}`)
 
@@ -70,5 +70,3 @@ function multer (options = {}) {
 
   return new Multer(options)
 }
-
-module.exports = multer

lib/error.js

@@ -8,7 +8,7 @@ const errorMessages = new Map([
   ['LIMIT_UNEXPECTED_FILE', 'Unexpected file field']
 ])
 
-class MulterError extends Error {
+export default class MulterError extends Error {
   constructor (code, optionalField) {
     super(errorMessages.get(code))
 
@@ -19,5 +19,3 @@ class MulterError extends Error {
     Error.captureStackTrace(this, this.constructor)
   }
 }
-
-module.exports = MulterError

lib/file-appender.js

@@ -1,10 +1,10 @@
-function createFileAppender (strategy, req, fields) {
+export default function createFileAppender (strategy, req, fields) {
   switch (strategy) {
     case 'NONE': break
     case 'VALUE': req.file = null; break
     case 'ARRAY': req.files = []; break
     case 'OBJECT': req.files = Object.create(null); break
-    // istanbul ignore next
+    /* c8 ignore next */
     default: throw new Error(`Unknown file strategy: ${strategy}`)
   }
 
@@ -22,5 +22,3 @@ function createFileAppender (strategy, req, fields) {
     }
   }
 }
-
-module.exports = createFileAppender

lib/file-filter.js

@@ -1,6 +1,6 @@
-const MulterError = require('./error')
+import MulterError from './error.js'
 
-function createFileFilter (fields) {
+export default function createFileFilter (fields) {
   const filesLeft = new Map()
 
   for (const field of fields) {
@@ -25,5 +25,3 @@ function createFileFilter (fields) {
     filesLeft.set(file.fieldName, left - 1)
   }
 }
-
-module.exports = createFileFilter

lib/middleware.js

@@ -1,9 +1,10 @@
-const is = require('type-is')
-const fs = require('fs')
-const appendField = require('append-field')
+import fs from 'node:fs'
 
-const createFileAppender = require('./file-appender')
-const readBody = require('./read-body')
+import appendField from 'append-field'
+import is from 'type-is'
+
+import createFileAppender from './file-appender.js'
+import readBody from './read-body.js'
 
 async function handleRequest (setup, req) {
   const options = setup()
@@ -25,11 +26,9 @@ async function handleRequest (setup, req) {
   }
 }
 
-function createMiddleware (setup) {
-  return function multerMiddleware (req, res, next) {
+export default function createMiddleware (setup) {
+  return function multerMiddleware (req, _, next) {
     if (!is(req, ['multipart'])) return next()
     handleRequest(setup, req).then(next, next)
   }
 }
-
-module.exports = createMiddleware

lib/read-body.js

@@ -1,14 +1,16 @@
-const path = require('path')
-const pify = require('pify')
-const temp = require('fs-temp')
-const Busboy = require('busboy')
-const FileType = require('stream-file-type')
-const hasOwnProperty = require('has-own-property')
+import { extname } from 'node:path'
+import { pipeline } from 'node:stream/promises'
+import { promisify } from 'node:util'
 
-const pump = pify(require('pump'))
-const onFinished = pify(require('on-finished'))
+import Busboy from 'busboy'
+import { createWriteStream } from 'fs-temp'
+import hasOwnProperty from 'has-own-property'
+import _onFinished from 'on-finished'
+import FileType from 'stream-file-type'
 
-const MulterError = require('./error')
+import MulterError from './error.js'
+
+const onFinished = promisify(_onFinished)
 
 function drainStream (stream) {
   stream.on('readable', stream.read.bind(stream))
@@ -19,7 +21,8 @@ function collectFields (busboy, limits) {
     const result = []
 
     busboy.on('field', (fieldname, value, fieldnameTruncated, valueTruncated) => {
-      // istanbul ignore next: Currently not implemented (https://github.com/mscdex/busboy/issues/6)
+      // Currently not implemented (https://github.com/mscdex/busboy/issues/6)
+      /* c8 ignore next */
       if (fieldnameTruncated) return reject(new MulterError('LIMIT_FIELD_KEY'))
 
       if (valueTruncated) return reject(new MulterError('LIMIT_FIELD_VALUE', fieldname))
@@ -58,7 +61,7 @@ function collectFiles (busboy, limits, fileFilter) {
         fieldName: fieldname,
         originalName: filename,
         clientReportedMimeType: mimetype,
-        clientReportedFileExtension: path.extname(filename || '')
+        clientReportedFileExtension: extname(filename || '')
       }
 
       try {
@@ -67,11 +70,11 @@ function collectFiles (busboy, limits, fileFilter) {
         return reject(err)
       }
 
-      const target = temp.createWriteStream()
+      const target = createWriteStream()
       const detector = new FileType()
       const fileClosed = new Promise((resolve) => target.on('close', resolve))
 
-      const promise = pump(fileStream, detector, target)
+      const promise = pipeline(fileStream, detector, target)
         .then(async () => {
           await fileClosed
           file.path = target.path
@@ -92,7 +95,7 @@ function collectFiles (busboy, limits, fileFilter) {
   })
 }
 
-async function readBody (req, limits, fileFilter) {
+export default async function readBody (req, limits, fileFilter) {
   const busboy = new Busboy({ headers: req.headers, limits: limits })
 
   const fields = collectFields(busboy, limits)
@@ -119,10 +122,8 @@ async function readBody (req, limits, fileFilter) {
     busboy.removeAllListeners()
 
     // Wait for request to close, finish, or error
-    await onFinished(req).catch(/* istanbul ignore next: Already handled by req.on('error', _) */ () => {})
+    await onFinished(req).catch(/* c8 ignore next: Already handled by req.on('error', _) */ () => {})
 
     throw err
   }
 }
-
-module.exports = readBody

package.json

@@ -9,6 +9,8 @@
   ],
   "license": "MIT",
   "repository": "expressjs/multer",
+  "type": "module",
+  "exports": "./index.js",
   "keywords": [
     "form",
     "post",
@@ -19,38 +21,35 @@
     "middleware"
   ],
   "dependencies": {
-    "append-field": "^1.0.0",
+    "append-field": "^2.0.0",
     "busboy": "^0.3.1",
     "bytes": "^3.1.0",
-    "fs-temp": "^1.1.1",
-    "has-own-property": "^1.0.0",
+    "fs-temp": "^2.0.0",
+    "has-own-property": "^2.0.0",
     "on-finished": "^2.3.0",
-    "pify": "^5.0.0",
-    "pump": "^3.0.0",
-    "stream-file-type": "^0.5.0",
+    "stream-file-type": "^0.6.1",
     "type-is": "^1.6.18"
   },
   "devDependencies": {
-    "assert-rejects": "^1.0.0",
+    "c8": "^7.7.3",
     "express": "^4.16.4",
-    "form-data": "^3.0.0",
-    "get-stream": "^5.1.0",
+    "form-data": "^4.0.0",
+    "get-stream": "^6.0.1",
     "hasha": "^5.2.0",
-    "mocha": "^7.1.0",
-    "nyc": "^15.0.0",
+    "mocha": "^9.0.3",
     "recursive-nullify": "^1.0.0",
-    "standard": "^14.3.3",
+    "standard": "^16.0.3",
     "testdata-w3c-json-form": "^1.0.0"
   },
   "engines": {
-    "node": ">=10.13"
+    "node": "^12.20.0 || ^14.13.1 || >=16.0.0"
   },
   "files": [
     "LICENSE",
     "index.js",
     "lib/"
   ],
   "scripts": {
-    "test": "standard && nyc --check-coverage --statements 100 mocha"
+    "test": "standard && c8 --check-coverage --statements 100 mocha"
   }
 }

test/_util.js

@@ -1,11 +1,12 @@
-const fs = require('fs')
-const path = require('path')
-const pify = require('pify')
-const hasha = require('hasha')
-const assert = require('assert')
-const stream = require('stream')
+import assert from 'node:assert'
+import fs from 'node:fs'
+import stream from 'node:stream'
+import { promisify } from 'node:util'
 
-const onFinished = pify(require('on-finished'))
+import hasha from 'hasha'
+import _onFinished from 'on-finished'
+
+const onFinished = promisify(_onFinished)
 
 const files = new Map([
   ['empty', {
@@ -50,15 +51,15 @@ const files = new Map([
   }]
 ])
 
-exports.file = function file (name) {
-  return fs.createReadStream(path.join(__dirname, 'files', name + files.get(name).extension))
+export function file (name) {
+  return fs.createReadStream(new URL(`files/${name}${files.get(name).extension}`, import.meta.url))
 }
 
-exports.knownFileLength = function knownFileLength (name) {
+export function knownFileLength (name) {
   return files.get(name).size
 }
 
-exports.assertFile = async (file, fieldName, fileName) => {
+export async function assertFile (file, fieldName, fileName) {
   if (!files.has(fileName)) {
     throw new Error(`No file named "${fileName}"`)
   }
@@ -80,15 +81,15 @@ exports.assertFile = async (file, fieldName, fileName) => {
   assert.strictEqual(hash, expected.hash)
 }
 
-exports.assertFiles = (files) => {
-  return Promise.all(files.map((args) => exports.assertFile(args[0], args[1], args[2])))
+export async function assertFiles (files) {
+  await Promise.all(files.map((args) => assertFile(args[0], args[1], args[2])))
 }
 
 function getLength (form) {
-  return pify(form.getLength).call(form)
+  return promisify(form.getLength).call(form)
 }
 
-exports.submitForm = async (multer, form) => {
+export async function submitForm (multer, form) {
   const length = await getLength(form)
   const req = new stream.PassThrough()
 
@@ -101,7 +102,7 @@ exports.submitForm = async (multer, form) => {
     'content-length': length
   }
 
-  await pify(multer)(req, null)
+  await promisify(multer)(req, null)
   await onFinished(req)
 
   return req

test/aborted-requests.js

@@ -1,15 +1,16 @@
 /* eslint-env mocha */
 
-const util = require('./_util')
-const multer = require('../')
+import assert from 'node:assert'
+import { PassThrough } from 'node:stream'
+import { promisify } from 'node:util'
 
-const assertRejects = require('assert-rejects')
-const FormData = require('form-data')
-const PassThrough = require('stream').PassThrough
-const pify = require('pify')
+import FormData from 'form-data'
+
+import * as util from './_util.js'
+import multer from '../index.js'
 
 function getLength (form) {
-  return pify(form.getLength).call(form)
+  return promisify(form.getLength).call(form)
 }
 
 function createAbortStream (maxBytes, aborter) {
@@ -50,9 +51,9 @@ describe('Aborted requests', () => {
       'content-length': length
     }
 
-    const result = pify(parser)(form.pipe(req), null)
+    const result = promisify(parser)(form.pipe(req), null)
 
-    return assertRejects(result, err => err.code === 'CLIENT_ABORTED')
+    return assert.rejects(result, err => err.code === 'CLIENT_ABORTED')
   })
 
   it('should handle clients erroring the request', async () => {
@@ -69,8 +70,8 @@ describe('Aborted requests', () => {
       'content-length': length
     }
 
-    const result = pify(parser)(form.pipe(req), null)
+    const result = promisify(parser)(form.pipe(req), null)
 
-    return assertRejects(result, err => err.message === 'TEST_ERROR')
+    return assert.rejects(result, err => err.message === 'TEST_ERROR')
   })
 })