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Awesome Open Source


Pure JavaScript Iconv for Japanese encodings.

Build Status Npm Modules MIT Licensed

  • This module supports the encodings commonly used in the Japanese Language:
    Shift_JIS(CP932), ISO-2022-JP(-1), EUC-JP, UTF8, UNICODE(UCS2) conversion.
  • Pure Javascript, no need to compile.
  • Much faster than node-iconv.

[Japanese 日本語]


$ npm install jconv


For example simply convert from EUC-JP to Shift_JIS:

var jconv = require( 'jconv' );

var SJISBuffer = jconv.convert( EUCJPBuffer, 'EUCJP', 'SJIS' );

Also available iconv-lite syntax:

var str = jconv.decode( buffer, fromEncoding );

var buf = jconv.encode( 'string', toEncoding );


  • jconv( input, fromEncoding, toEncoding )

  • jconv.convert( input, fromEncoding, toEncoding )

    • input {Buffer} or {String}
    • fromEncoding, toEncoding {String}:
      Shift_JIS(SJIS), ISO-2022-JP(JIS), EUCJP, UTF8, UNICODE(UCS2, UTF16LE) are available.
    • return {Buffer}
  • jconv.decode( inputBuffer, fromEncoding )

    • return {String}
  • jconv.encode( inputString, toEncoding )

    • return {Buffer}
  • jconv.encodingExists( encodingName )

    • return {Boolean}


Comparison with [email protected] by converting Japanese text using Benchmark.js.
Environment is Windows7, core i5 2405-S, mem8G, Node 0.10.22. (Please check on your hardware.)
Gray: iconv, Blue: jconv (higher is better)

jconv - encoding speed test chart [latest log]


  • Supported: Shift_JIS(CP932), ISO-2022-JP(-1), EUC-JP, UTF8, UNICODE(UCS2).

  • Supported Windows Dependent Characters <-> JIS Conversion.
    (problem details)

  • "JIS X 0208", "JIS X 0212" and "CP932" have the Unicode Mapping Table Differences, so the specific characters ( ~¢£∥ etc... ) cannot be round-trip converted by default.
    This module corrects this difference as much as possible when converting.
    (problem details)


  • Clone Repository
git clone  
cd jconv  
npm install
  • Generate Tables
# generates the unicode mapping table module in "tables" folder.
node generators/generate-source  
node generators/generate
  • Test
grunt test
  • Speed Test
# First, minify the script by closure-compiler.
grunt minify
node test/speed  
# This results are visualized by chart.js.  
# Plese open "chart/index.html".

Based on

Thank you so much!


Pull requests are welcome.


  • Streaming API support
  • Support more encodings and languages.
  • Cleanup the code and more speed.

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javascript (70,402
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