# MIME Codec [![Greenkeeper badge](https://badges.greenkeeper.io/emailjs/emailjs-mime-codec.svg)](https://greenkeeper.io/) [![Build Status](https://travis-ci.org/emailjs/emailjs-mime-codec.png?branch=master)](https://travis-ci.org/emailjs/emailjs-mime-codec) [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com) [![ES6+](https://camo.githubusercontent.com/567e52200713e0f0c05a5238d91e1d096292b338/68747470733a2f2f696d672e736869656c64732e696f2f62616467652f65732d362b2d627269676874677265656e2e737667)](https://kangax.github.io/compat-table/es6/) `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 ```javascript 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](https://tools.ietf.org/html/rfc2231#section-3) 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 ```javascript parseHeaderValue('content-type: text/plain; CHARSET="UTF-8"'); ``` Outputs ```json { "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.```