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Node.js Version of MMSG for Chinese Word Segmentation

Build Status

MMSG originally invented by Chih-Hao Tsai is a very popular Chinese word segmentation algorithm. Many implementations are available on different platforms including Python, Java, etc.

This package provide Node.js version of MMSG algorithm. The API is async and evented sytle.

So far this package is still in developing, but the basic functionalities are ready.


Use nseg in your own package

$ npm install nseg

Or if you want to use nseg command

$ npm install -g nseg

Command line

After intsalling globally, you can use nseg command to:


$ nseg help

segment text using default dictionary

$ nseg segf -i ~/project/text/shi.txt -o ~/project/output/shi.txt
$ nseg segd -i ~/project/text -o ~/project/output

build user dictionary for loading aftermath

$ nseg dict ~/project/data/dict.js ~/dict/dict1.txt ~/dict/dict2.txt
$ nseg dict ~/project/data/dict.js ~/dict

build character-frequecy map for loading aftermath

$ nseg freq ~/project/data/freq.js ~/freq/data1.csv ~/freq/data2.csv
$ nseg freq ~/project/data/freq.js ~/freq

segment text using customized settings

$ nseg segd -d ~/project/data/dict.js -f ~/project/data/freq.js -i ~/project/text -o ~/project/output
$ nseg segd -l ~/project/lex/ -i ~/project/text -o ~/project/output

check the existence of a word

$ nseg check "石狮"
$ nseg check -d ~/project/data/dict.js "石狮"

Using nseg in program


  • (Optional) build your own dictionay and freqency map
  • (Optional) create your own lexical handler for special text pattern


Stream-pipe style

var dict  = require('../data/dict'),
    freq  = require('../data/freq'),
    date  = require('../lex/datetime'),
    sina  = require('../lex/sina');
var opts  = {
        dict: dict,
        freq: freq,
        lexers: [date, sina],
var nseg = require('nseg').evented(opts);
var strmOut = fs.createWriteStream(target, {flags: 'w+', encoding: 'utf-8'}),
    strmIn  = fs.createReadStream(input);
var pipe = nseg(strmIn, strmOut);
pipe.on('error', function (err) {
    console.log('error', err);

Normal callback style (buggy)

var dict  = require('../data/dict'),
    freq  = require('../data/freq'),
    date  = require('../lex/datetime'),
    sina  = require('../lex/sina');
var opts  = {
        dict: dict,
        freq: freq,
        lexers: [date, sina],
var nseg = require('nseg').normal(opts);
nseg('研究生源计划', function (result) {

Lexical handler customization

Lexical handlers support definitions by acceptor functions.

An acceptor function is a function with signature of

function accept(curchar, undecidedprefix, nextchar)

And return value should be one value from -1, 0, 1 on case of:

  • -1: we can decide a negitive result for the current character.
  • 0 : we should read more characters.
  • 1 : we can decide a negitive result for the current character.


MIT License