FormData.js

/* formdata-polyfill. MIT License. Jimmy Wärting <https://jimmy.warting.se/opensource> */

/* global FormData self Blob File */
/* eslint-disable no-inner-declarations */

if (typeof Blob !== 'undefined' && (typeof FormData === 'undefined' || !FormData.prototype.keys)) {
  const global = typeof globalThis === 'object'
    ? globalThis
    : typeof window === 'object'
      ? window
      : typeof self === 'object' ? self : this

  // keep a reference to native implementation
  const _FormData = global.FormData

  // To be monkey patched
  const _send = global.XMLHttpRequest && global.XMLHttpRequest.prototype.send
  const _fetch = global.Request && global.fetch
  const _sendBeacon = global.navigator && global.navigator.sendBeacon
  // Might be a worker thread...
  const _match = global.Element && global.Element.prototype

  // Unable to patch Request/Response constructor correctly #109
  // only way is to use ES6 class extend
  // https://github.com/babel/babel/issues/1966

  const stringTag = global.Symbol && Symbol.toStringTag

  // Add missing stringTags to blob and files
  if (stringTag) {
    if (!Blob.prototype[stringTag]) {
      Blob.prototype[stringTag] = 'Blob'
    }

    if ('File' in global && !File.prototype[stringTag]) {
      File.prototype[stringTag] = 'File'
    }
  }

  // Fix so you can construct your own File
  try {
    new File([], '') // eslint-disable-line
  } catch (a) {
    global.File = function File (b, d, c) {
      const blob = new Blob(b, c || {})
      const t = c && void 0 !== c.lastModified ? new Date(c.lastModified) : new Date()

      Object.defineProperties(blob, {
        name: {
          value: d
        },
        lastModified: {
          value: +t
        },
        toString: {
          value () {
            return '[object File]'
          }
        }
      })

      if (stringTag) {
        Object.defineProperty(blob, stringTag, {
          value: 'File'
        })
      }

      return blob
    }
  }

  function ensureArgs (args, expected) {
    if (args.length < expected) {
      throw new TypeError(`${expected} argument required, but only ${args.length} present.`)
    }
  }

  /**
   * @param {string} name
   * @param {string | undefined} filename
   * @returns {[string, File|string]}
   */
  function normalizeArgs (name, value, filename) {
    if (value instanceof Blob) {
      filename = filename !== undefined
      ? String(filename + '')
      : typeof value.name === 'string'
      ? value.name
      : 'blob'

      if (value.name !== filename || Object.prototype.toString.call(value) === '[object Blob]') {
        value = new File([value], filename)
      }
      return [String(name), value]
    }
    return [String(name), String(value)]
  }

  // normalize line feeds for textarea
  // https://html.spec.whatwg.org/multipage/form-elements.html#textarea-line-break-normalisation-transformation
  function normalizeLinefeeds (value) {
    return value.replace(/\r?\n|\r/g, '\r\n')
  }

  /**
   * @template T
   * @param {ArrayLike<T>} arr
   * @param {{ (elm: T): void; }} cb
   */
  function each (arr, cb) {
    for (let i = 0; i < arr.length; i++) {
      cb(arr[i])
    }
  }

  const escape = str => str.replace(/\n/g, '%0A').replace(/\r/g, '%0D').replace(/"/g, '%22')

  /**
   * @implements {Iterable}
   */
  class FormDataPolyfill {
    /**
     * FormData class
     *
     * @param {HTMLFormElement=} form
     */
    constructor (form) {
      /** @type {[string, string|File][]} */
      this._data = []

      const self = this
      form && each(form.elements, (/** @type {HTMLInputElement} */ elm) => {
        if (
          !elm.name ||
          elm.disabled ||
          elm.type === 'submit' ||
          elm.type === 'button' ||
          elm.matches('form fieldset[disabled] *')
        ) return

        if (elm.type === 'file') {
          const files = elm.files && elm.files.length
            ? elm.files
            : [new File([], '', { type: 'application/octet-stream' })] // #78

          each(files, file => {
            self.append(elm.name, file)
          })
        } else if (elm.type === 'select-multiple' || elm.type === 'select-one') {
          each(elm.options, opt => {
            !opt.disabled && opt.selected && self.append(elm.name, opt.value)
          })
        } else if (elm.type === 'checkbox' || elm.type === 'radio') {
          if (elm.checked) self.append(elm.name, elm.value)
        } else {
          const value = elm.type === 'textarea' ? normalizeLinefeeds(elm.value) : elm.value
          self.append(elm.name, value)
        }
      })
    }

    /**
     * Append a field
     *
     * @param   {string}           name      field name
     * @param   {string|Blob|File} value     string / blob / file
     * @param   {string=}          filename  filename to use with blob
     * @return  {undefined}
     */
    append (name, value, filename) {
      ensureArgs(arguments, 2)
      this._data.push(normalizeArgs(name, value, filename))
    }

    /**
     * Delete all fields values given name
     *
     * @param   {string}  name  Field name
     * @return  {undefined}
     */
    delete (name) {
      ensureArgs(arguments, 1)
      const result = []
      name = String(name)

      each(this._data, entry => {
        entry[0] !== name && result.push(entry)
      })

      this._data = result
    }

    /**
     * Iterate over all fields as [name, value]
     *
     * @return {Iterator}
     */
    * entries () {
      for (var i = 0; i < this._data.length; i++) {
        yield this._data[i]
      }
    }

    /**
     * Iterate over all fields
     *
     * @param   {Function}  callback  Executed for each item with parameters (value, name, thisArg)
     * @param   {Object=}   thisArg   `this` context for callback function
     */
    forEach (callback, thisArg) {
      ensureArgs(arguments, 1)
      for (const [name, value] of this) {
        callback.call(thisArg, value, name, this)
      }
    }

    /**
     * Return first field value given name
     * or null if non existent
     *
     * @param   {string}  name      Field name
     * @return  {string|File|null}  value Fields value
     */
    get (name) {
      ensureArgs(arguments, 1)
      const entries = this._data
      name = String(name)
      for (let i = 0; i < entries.length; i++) {
        if (entries[i][0] === name) {
          return entries[i][1]
        }
      }
      return null
    }

    /**
     * Return all fields values given name
     *
     * @param   {string}  name  Fields name
     * @return  {Array}         [{String|File}]
     */
    getAll (name) {
      ensureArgs(arguments, 1)
      const result = []
      name = String(name)
      each(this._data, data => {
        data[0] === name && result.push(data[1])
      })

      return result
    }

    /**
     * Check for field name existence
     *
     * @param   {string}   name  Field name
     * @return  {boolean}
     */
    has (name) {
      ensureArgs(arguments, 1)
      name = String(name)
      for (let i = 0; i < this._data.length; i++) {
        if (this._data[i][0] === name) {
          return true
        }
      }
      return false
    }

    /**
     * Iterate over all fields name
     *
     * @return {Iterator}
     */
    * keys () {
      for (const [name] of this) {
        yield name
      }
    }

    /**
     * Overwrite all values given name
     *
     * @param   {string}    name      Filed name
     * @param   {string}    value     Field value
     * @param   {string=}   filename  Filename (optional)
     */
    set (name, value, filename) {
      ensureArgs(arguments, 2)
      name = String(name)
      /** @type {[string, string|File][]} */
      const result = []
      const args = normalizeArgs(name, value, filename)
      let replace = true

      // - replace the first occurrence with same name
      // - discards the remaining with same name
      // - while keeping the same order items where added
      each(this._data, data => {
        data[0] === name
          ? replace && (replace = !result.push(args))
          : result.push(data)
      })

      replace && result.push(args)

      this._data = result
    }

    /**
     * Iterate over all fields
     *
     * @return {Iterator}
     */
    * values () {
      for (const [, value] of this) {
        yield value
      }
    }

    /**
     * Return a native (perhaps degraded) FormData with only a `append` method
     * Can throw if it's not supported
     *
     * @return {FormData}
     */
    ['_asNative'] () {
      const fd = new _FormData()

      for (const [name, value] of this) {
        fd.append(name, value)
      }

      return fd
    }

    /**
     * [_blob description]
     *
     * @return {Blob} [description]
     */
    ['_blob'] () {
        const boundary = '----formdata-polyfill-' + Math.random(),
          chunks = [],
          p = `--${boundary}\r\nContent-Disposition: form-data; name="`
        this.forEach((value, name) => typeof value == 'string'
          ? chunks.push(p + escape(normalizeLinefeeds(name)) + `"\r\n\r\n${normalizeLinefeeds(value)}\r\n`)
          : chunks.push(p + escape(normalizeLinefeeds(name)) + `"; filename="${escape(value.name)}"\r\nContent-Type: ${value.type||"application/octet-stream"}\r\n\r\n`, value, `\r\n`))
        chunks.push(`--${boundary}--`)
        return new Blob(chunks, {
          type: "multipart/form-data; boundary=" + boundary
        })
    }

    /**
     * The class itself is iterable
     * alias for formdata.entries()
     *
     * @return {Iterator}
     */
    [Symbol.iterator] () {
      return this.entries()
    }

    /**
     * Create the default string description.
     *
     * @return  {string} [object FormData]
     */
    toString () {
      return '[object FormData]'
    }
  }

  if (_match && !_match.matches) {
    _match.matches =
      _match.matchesSelector ||
      _match.mozMatchesSelector ||
      _match.msMatchesSelector ||
      _match.oMatchesSelector ||
      _match.webkitMatchesSelector ||
      function (s) {
        var matches = (this.document || this.ownerDocument).querySelectorAll(s)
        var i = matches.length
        while (--i >= 0 && matches.item(i) !== this) {}
        return i > -1
      }
  }

  if (stringTag) {
    /**
     * Create the default string description.
     * It is accessed internally by the Object.prototype.toString().
     */
    FormDataPolyfill.prototype[stringTag] = 'FormData'
  }

  // Patch xhr's send method to call _blob transparently
  if (_send) {
    const setRequestHeader = global.XMLHttpRequest.prototype.setRequestHeader

    global.XMLHttpRequest.prototype.setRequestHeader = function (name, value) {
      setRequestHeader.call(this, name, value)
      if (name.toLowerCase() === 'content-type') this._hasContentType = true
    }

    global.XMLHttpRequest.prototype.send = function (data) {
      // need to patch send b/c old IE don't send blob's type (#44)
      if (data instanceof FormDataPolyfill) {
        const blob = data['_blob']()
        if (!this._hasContentType) this.setRequestHeader('Content-Type', blob.type)
        _send.call(this, blob)
      } else {
        _send.call(this, data)
      }
    }
  }

  // Patch fetch's function to call _blob transparently
  if (_fetch) {
    global.fetch = function (input, init) {
      if (init && init.body && init.body instanceof FormDataPolyfill) {
        init.body = init.body['_blob']()
      }

      return _fetch.call(this, input, init)
    }
  }

  // Patch navigator.sendBeacon to use native FormData
  if (_sendBeacon) {
    global.navigator.sendBeacon = function (url, data) {
      if (data instanceof FormDataPolyfill) {
        data = data['_asNative']()
      }
      return _sendBeacon.call(this, url, data)
    }
  }

  global['FormData'] = FormDataPolyfill
}