emailjs-mime-codec

emailjs-mime-codec allows you to encode and decode between different MIME related encodings. Quoted-Printable, Base64 etc.
All input can use any charset (in this case, the value must not be a string but an arraybuffer of Uint8Array) but output is always unicode.

Usage

npm install --save emailjs-mime-codec

import {
  encode, decode, convert
  mimeEncode, mimeDecode,
  base64Encode, base64Decode,
  quotedPrintableEncode, quotedPrintableDecode,
  mimeWordEncode, mimeWordDecode,
  mimeWordsEncode, mimeWordsDecode,
  headerLineEncode, headerLinesDecode,
  continuationEncode,
  foldLines,
  parseHeaderValue
} from 'emailjs-mime-codec'

Charset functions

encode(data: String) -> Uint8Array
decode(data: Uint8Array, charset: String) -> String
convert(data, charset: String) -> String

encode takes a String and returns a UTF-8 encoded Uint8Array.
decode takes a Uint8Array along with a charset and decodes the typed array to a String. Charset defaults to UTF-8.
convert chains encode and decode and converts an input string with a given encoding to a UTF-8 encoded Uint8Array.

foldLines

Folds a long line according to the RFC 5322

foldLines(str [, lineLengthMax[, afterSpace]]) -> String

str - String to be folded lineLengthMax - Maximum length of a line (defaults to 76) afterSpace - If true, leave a space in th end of a line
For example:

foldLines('Content-Type: multipart/alternative; boundary="----zzzz----"')

results in

Content-Type: multipart/alternative;
     boundary="----zzzz----"

mimeWordEncode

Encodes a string into mime encoded word format (see also mimeWordDecode)

mimeWordEncode(str [, mimeWordEncoding[, fromCharset]]) -> String

str - String or Uint8Array to be encoded mimeWordEncoding - Encoding for the mime word, either Q or B (default is 'Q') fromCharset - If the first parameter is a typed array, use this encoding to decode the value to unicode
For example:

mimeWordEncode('See on õhin test', 'Q');

Becomes with UTF-8 and Quoted-printable encoding

=?UTF-8?Q?See_on_=C3=B5hin_test?=

mimeWordDecode

Decodes a string from mime encoded word format (see also mimeWordEncode)

mimeWordDecode(str) -> String

str - String to be decoded
For example

mimeWordDecode('=?UTF-8?Q?See_on_=C3=B5hin_test?=');

will become

See on õhin test

continuationEncode

Encodes and splits a header param value according to RFC2231 Parameter Value Continuations.

continuationEncode(key, str [, fromCharset]) -> Array

key - Parameter key (eg. filename) str - String or an Uint8Array value to encode fromCharset - If str is a typed array, use this charset to decode the value to unicode before encoding
The method returns an array of encoded parts with the following structure: [{key:'...', value: '...'}]

Example

continuationEncode('filename', 'filename õäöü.txt', 20);
->
[ { key: 'filename*0*', value: 'utf-8\'\'filename%20' },
  { key: 'filename*1*', value: '%C3%B5%C3%A4%C3%B6' },
  { key: 'filename*2*', value: '%C3%BC.txt' } ]

This can be combined into a properly formatted header:

Content-disposition: attachment; filename*0*="utf-8''filename%20"
  filename*1*="%C3%B5%C3%A4%C3%B6"; filename*2*="%C3%BC.txt"

quotedPrintableEncode

Encodes a string into Quoted-printable format (see also quotedPrintableDecode). Maximum line length for the generated string is 76 + 2 bytes.

quotedPrintableEncode(str [, fromCharset]) -> String

str - String or an Uint8Array to mime encode fromCharset - If the first parameter is a typed array, use this charset to decode the value to unicode before encoding

quotedPrintableDecode

Decodes a string from Quoted-printable format (see also quotedPrintableEncode).

quotedPrintableDecode(str [, fromCharset]) -> String

str - Mime encoded string fromCharset - Use this charset to decode mime encoded string to unicode

base64Encode

Encodes a string into Base64 format (see also base64Decode). Maximum line length for the generated string is 76 + 2 bytes.

base64Encode(str [, fromCharset]) -> String

str - String or an Uint8Array to base64 encode fromCharset - If the first parameter is a typed array, use this charset to decode the value to unicode before encoding

base64Decode

Decodes a string from Base64 format (see also base64Encode) to an unencoded unicode string.

base64Decode(str [, fromCharset]) -> String

str Base64 encoded string fromCharset Use this charset to decode base64 encoded string to unicode

mimeWordEncode

Encodes a string to a mime word.

mimeWordEncode(str[, mimeWordEncoding[, fromCharset]]) -> String

str - String or Uint8Array to be encoded mimeWordEncoding - Encoding for the mime word, either Q or B (default is 'Q') fromCharset - If the first parameter is a typed array, use this charset to decode the value to unicode before encoding

mimeWordsEncode

Encodes non ascii sequences in a string to mime words.

mimeWordsEncode(str[, mimeWordEncoding[, fromCharset]]) -> String

str - String or Uint8Array to be encoded mimeWordEncoding - Encoding for the mime word, either Q or B (default is 'Q') fromCharset - If the first parameter is a typed array, use this charset to decode the value to unicode before encoding

mimeWordDecode

Decodes a complete mime word encoded string

mimeWordDecode(str) -> String

str - String to be decoded. Mime words have charset information included so need to specify it here

mimeWordsDecode

Decodes a string that might include one or several mime words. If no mime words are found from the string, the original string is returned

mimeWordsDecode(str) -> String

str - String to be decoded

headerLineEncode

Encodes and folds a header line for a MIME message header. Shorthand for mimeWordsEncode + foldLines.

headerLineEncode(key, value[, fromCharset])

key - Key name, will not be encoded value - Value to be encoded fromCharset - If the value parameter is a typed array, use this charset to decode the value to unicode before encoding

headerLinesDecode

Parses a block of header lines. Does not decode mime words as every header might have its own rules (eg. formatted email addresses and such).
Return value is an object of headers, where header keys are object keys. NB! Several values with the same key make up an array of values for the same key.

headerLinesDecode(headers) -> Object

headers - Headers string

parseHeaderValue

Parses a header value with key=value arguments into a structured object. Useful when dealing with content-type and such.

parseHeaderValue(valueString) -> Object

valueString - a header value without the key
Example

parseHeaderValue('content-type: text/plain; CHARSET="UTF-8"');

Outputs

{
    "value": "text/plain",
    "params": {
        "charset": "UTF-8"
    }
}

License

``` The MIT License
Copyright (c) 2013 Andris Reinman
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.```